20251209APPLICATION.pdf

RECEIVED
Avista Corp. December 9, 2025
1411 East Mission P.O. Box 3727 IDAHO PUBLIC
Spokane, Washington 99220-0500 UTILITIES COMMISSION
Telephone [phone]
Toll Free 800-727-9170
December 9, 2025
State of Idaho
Idaho Public Utilities Commission
11331 W. Chinden Blvd
Bldg 8 Suite 201-A
Boise, ID 83714
RE: Case No. AVU-E-25-15 —Avista Corporation's 2026 Wildfire Mitigation Plan
Dear Commission Secretary:
Attached please find Avista Corporation's Application to be filed in the above case.
Please direct any questions related to the transmittal of this filing to Liz Andrews at 509-495-
8601.
Sincerely,
lsl 5*ka 4"dz w
Elizabeth Andrews
Sr. Manager of Revenue Requirements
liz.andrews@avistaco!p.com

ANNI GLOGOVAC, ISB #13010
COUNSEL FOR REGULATORY AFFAIRS
AVISTA CORPORATION
1411 E. MISSION AVENUE
P.O. BOX 3727
SPOKANE, WASHINGTON 99220
PHONE: [phone]
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF AVISTA ) CASE NO. AVU-E-25-15
CORPORATION'S 2026 WILDFIRE )
MITIGATION PLAN ) APPLICATION
I. INTRODUCTION
COMES NOW, Avista Corporation ("Avista" or "Company"), in accordance with the
Idaho Public Utilities Commission("Commission" or"IPUC") Rule of Procedure' ("RP") 52 and
Order No. 36774,2 respectively submits its 2026 Wildfire Mitigation Plan ("WMP" or "Wildfire
Plan"), included as Attachment A, and requests the Commission issue an order approving said
plan.
Although Avista's 2026 Avista Wildfire Mitigation Plan is its fifth edition of the plan, it is
the first being filed for approval pursuant to the Wildfire Standard of Care Act ("WSCA"), Idaho
Code §61-1801 et seq. Pursuant to the WMP Filing Schedule adopted by the Commission,
Avista's WMP shall be filed with the Commission for review no earlier than November 1 st, with
updated WMPs filed annually, one year after filing the previously approved WMP. The Company
notes that the timing of its inaugural filing under the WSCA, while compliant with the
' Idaho Administrative Procedures Act(IDAPA)31.01.01.
2 In the Matter of Commission Staffs Application for Approval of a Filing Process for Wildfire Mitigation Plan, Case
No. GNR-E-25-02,Order No.36774(Sep.30,2025).
3 Exhibit A to Order No. 36774.
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 1

Commission-approved filing schedule,was postponed to ensure compliance with the Commission-
specific WMP ding requirements set forth in Order No. 36774 issued on September 30, 2025.
Moving forward, the Company intends to file its updated WMP for the Commission's annual
review on or about November 1st.
Avista is a utility that provides service to approximately 427,000 retail electric customers
and 385,000 retail natural gas customers in a 30,000 square-mile service territory covering portions
of Washington, Idaho, and Oregon. The largest community served by Avista is Spokane,
Washington, which is the location of its corporate headquarters.
Communications in reference to this Application should be addressed to:
Anni Glogovac Elizabeth Andrews
Counsel for Regulatory Affairs Senior Manager of Revenue Requirements
Avista Corporation Avista Corporation
P.O. Box 3727 P.O. Box 3727
1411 E. Mission Avenue, MSC 33 1411 E. Mission Avenue, MSC 27
Spokane, Washington 99220-3727 Spokane, Washington 99220-3727
Telephone: [phone] Telephone: [phone]
E-mail: anni.glo.og [e-mail] E-mail: [e-mail]
Avista Dockets (Electronic Only) [e-mail]
II. BACKGROUND
In support of this Application, Avista is submitting a Notice of Wildfire Mitigation Plan
Filing contemporaneously herewith and represents as follows:
The Western United States ("U.S.") has experienced an increase in the frequency and
intensity of wildland fires ("wildfires"). A variety of factors have contributed to this trend,
including changing climatic conditions,increased human encroachment in wildland areas, changes
in historical land management practices, and changes in wildland and forest health.
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 2

While Idaho has not experienced fires to the same magnitude as some other western states,4
Idaho's wildfire season has grown longer and more intense. Warmer temperatures, reduced
snowpack, and earlier snowmelt contribute to drier conditions, extending the period of heightened
fire risk.'
This Application is submitted in accordance with Idaho Code §61-1803(2)(a) and is
premised on the Company's continued efforts to reduce wildfire risk for the safety of Avista's
customers, the continued and reliable delivery of electricity to approximately 150,000 retail
electric customers in Idaho,and good stewardship of the beautiful and natural lands within Avista's
service area and beyond. Accordingly, the mitigation measures outlined in the Company's 2026
WMP are also intended to reduce potential risk associated with the Company's infrastructure or
equipment, such as the operation of its 180 substations (system), as well as approximately 900
miles of overhead transmission lines and 2,567 miles of overhead distribution lines within the state
of Idaho. These overhead assets represent about 40 percent of Avista's total overhead transmission
line assets and 33 percent of its total overhead distribution line assets.
The 2026 WMP is built around a geographical risk assessment, which utilizes a risk-
informed approach that considers wildfire probability and consequence to identify areas that may
be subject to potential heightened wildfire risk in locations where Avista has infrastructure or
equipment. Additionally, the Company employs a risk-informed cost and benefit balancing
approach to select and prioritize various wildfire mitigations carried out to reduce the risk of
wildfire.
As more thoroughly discussed in the Company's 2026 Wildfire Plan, and summarized
below, the WMP identifies the methods and means for mitigating wildfire risk that reflect a
4 Wildland Fire Summaries 2019-2024.htips://www.nifc.gov/fire-infonnation/statistics
5 Western Fire Chiefs Association.https://wfca.com/wildfire-articles/idaho-fire-season-in-depth- ug ide/
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 3

reasonable balancing of mitigation costs with the resulting reduction of wildfire risk, complying
with the requirements of Idaho Code §61-1803(3) and the additional directives from the
Commission set forth in Order No. 36774 issued in GNR-E-25-02 on September 30, 2025,
including the IPUC WMP Guidelines provided as Exhibit B to that order.
III. SUMMARY OF AVISTA'S WILDFIRE MITIGATION PLAN
As described in the WMP,Avista is focused on the safety of its customers and communities
and safely delivering reliable, affordable energy. The purpose of Avista's WMP is to guide
mitigation strategies and reduce risk. Over the past five years under its WMP, Avista has worked
to reduce wildfire risk by hardening its electrical system, expanding situational awareness
capabilities, upgrading the capabilities of the grid, and enhancing vegetation management
programs.
Furthermore, Avista's WMP is built on a foundation of proactive strategies and key
programs designed to implement these strategies. Avista's WMP takes a risk-based, regionally
tailored approach to reducing wildfire threats. Developed with input from internal experts and
industry peers, the WMP builds on proven practices while incorporating new technologies and
strategies to address the unique challenges of our service territory. By determining investment
priorities based on information such as mitigation effectiveness,cost-benefit analysis,and wildfire
risk throughout the service territory, the Wildfire Plan ensures that mitigation dollars are directed
toward the most impactful actions, maximizing safety, and the balance between cost and risk
reduction. Further, Avista has enhanced existing programs like Vegetation Management and Grid
Hardening, and has introduced new tools such as LiDAR, satellite imaging, and our Wildland
Urban Interface (WUI) map to better assess and manage risk. These efforts focus on high-risk
areas, in which 36 percent of our electric distribution system is located.
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 4

The key components of the Company's 2026 WMP are as follows:
• Situational Awareness
o Geographic risk assessment
o Weather stations
o Fire detection equipment
o Hourly fire risk modeling
• Grid Hardening
o Distribution and transmission construction strategies to prevent spark ignitions
o Sectionalization of circuits to isolate risk
o Improved communication to isolation devices
• Enhanced Vegetation Management
o Annual inspection and hazard mitigation to address vegetation risk
o Fuel reduction partnerships
• Operations and emergency response
o Use of protection settings including Public Safety Power Shutoff("PSPS") during
critical fire weather
o Communication plans
o Customer support programs
o Education and outreach
In addition, Avista's WMP focuses on the following goals:
1. Protecting Life and Property — To protect physical assets, property, and most
importantly, human lives, against the threat of wildfires; to recognize fire potential in our
operating and maintenance strategies; to take actions to reduce the risk of wildfire related
to interaction of Avista's system and the environment; and to minimize the impacts of
wildfire to Avista's infrastructure.
2. Emergency Preparedness — To recognize and react to wildfire as a recurring threat to
infrastructure,communities,and utility customers;to prepare and train for episodic wildfire
events and align operating practices with fire threat conditions to help mitigate wildfire
risk.
3. Financial Protection— To mitigate the probability and consequence of direct financial
costs and liability associated with large scale fire events.
Together,these key components and goals form a comprehensive and proactive strategy to
protect our customers, communities, and infrastructure from the growing threat of wildfire.
Attachment A includes Avista's 2026 Wildfire Mitigation Plan, and the following Appendices:
Appendix A: Commission Orders and Recommendations
Appendix B: State Budget& Targets
Appendix C: Third Party Undergrounding Report
Appendix D: Preventing &Mitigating Fires While Performing Avista Work
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 5

Appendix E: Avista Distribution Risk Tree Report
Appendix F: Public Safety Power Shut Off
IV.REQUIRED STAKEHOLDER COMMUNICATION
Idaho Code § 61-1804(2) requires electric corporations to provide notice to certain
interested parties within five days of filing a WMP for review and approval. Additionally, to
facilitate the participation of those interested parties in the review process, the Commission
adopted Staff s recommendation to include certain information in these notices. More specifically,
Staff recommended that the Commission require "each electric corporation' s notice to interested
entities to include information about how to participate in the Commission' s proceeding, the case
number, and provide a copy of the notice to the Commission in its filing.i6
Accordingly, and as required by Idaho Code § 61-1804(2) and pursuant to the additional
directive in Order No. 36774, Avista is providing notice of its WMP filing to the State forester,
cities, counties, fire protection districts, fire protection associations, and timber protection
associations within the Company's Idaho service area, which includes the case number for this
proceeding and information about how to participate in the Commission's proceeding; a copy of
the Company's letter, including a list of entities to which it is being provided, is attached to the
Company's Notice of Wildfire Mitigation Plan Filing filed contemporaneously herewith. Avista
believes this satisfies the requirements of Idaho Code §61-1804(2)and Order No. 36774;however,
the Company will, in the alternative, bring the WMP filing to the attention of interested entities
through any other means directed by the Commission.
6 GNR-E-25-02, Staff Comments at 15 (Aug. 21, 2025). The Company notes that the language in Order No. 36777
differs from the language in Staff s recommendation regarding the notice to interested parties required under Idaho
Code§ 61- 1804(2)and appears to contemplate an additional requirement of"notice to the Commission of the filing
of the WMP." To the extent the Commission did not intend to deviate from Staffs recommendation, the Company
respectfully requests the Commission issue an errata to Order No. 36774 aligning the ordering language related to
notice under Idaho Code § 61- 1804(2)with Staffs recommendation.
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 6

V. MODIFIED PROCEDURE
Avista believes that a technical hearing is not necessary to consider the issues presented
herein and respectfully requests that this Application be processed under Modified Procedure, i.e.,
by written submission rather than by hearing. PR 201, et. seq. However, the Company stands
ready to present testimony supporting this Application in a technical hearing if the Commission
determines such a hearing is required.
VI. CONCLUSION
Avista continues to take proactive measures to adjust to increasing wildfire risk, assessing
the magnitude of damage and loss of life associated with events outside of Idaho in recent years.
Taking actions to reduce the risk of wildfires is critical for Avista's customers, the communities
in which the Company operates, and to investors who provide capital to the Company.
Consistent with Idaho Code §61-1803(2)(a), the Company's WMP is the product of the
Company's comprehensive assessment of wildfire risk across its service area, using approaches
and methods that are commensurate with the size and complexity of the Company's operations and
specific fire risks present within its Idaho service territory. In its 2026 WMP, the Company has
identified several actions necessary to mitigate wildfire risk and protect the public interest that
reflect a reasonable balancing of mitigation costs. Specifically,Avista currently estimates spending
$7.2 million during 2026 in Operations and Maintenance ("O&M") expenses in Idaho ($18.5
million system) in further wildfire mitigation measures; however, this amount will likely change
in the future as the Company reviews and refines its WMP and associated mitigation activities. In
addition to 2026's estimated $18.5 million in system O&M expenses, Avista's wildfire mitigation
efforts also include capital investments in system infrastructure, many of which may also provide
additional benefits such as increased safety, reliability and resiliency of the system.
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 7

Accordingly, the Company requests the Commission review and issue an order approving
its 2026 WMP, finding it complies with Order No. 36774, as well as the WSCA, finding it meets
the minimum requirements stated in Idaho Code §61-1803; is consistent with public health, safety
and welfare; is feasibly implemented; and adequately minimizes wildfire risk and proposes to
respond to wildfires that do occur. The Company also requests the Commission clarify within its
order whether the Company can file its updated WMP for the Commission's annual review on or
about November 1"of each year going forward.
Respectfully submitted this 91h day of December, 2025.
L�M
Anni Glogovac
Counsel for Regulatory Affairs
ISB #13010
APPLICATION-WILDFIRE MITIGATION PLAN APPLICATION Page 8

BEFORE THE
IDAHO PUBLIC UTILITIES COMMISSION
CASE NO.AVU-E-25-15
ATTACHMENT A
AVISTA WILDFIRE MITIGATION PLAN AND APPENDICES

• /III ,
Wi I d f'r e iemdVISTa
Mitzagation
plan �!
i
Working2026
prepare
for . reduce
wildfire risk.

Table of Contents
Statement from Avista Executive Management................................................................................6
Introduction .......................................................................................................................................7
WildfirePlan Goals.............................................................................................................................7
Wildfire Program Elements Overview ...............................................................................................7
Commission Orders and Recommendations .....................................................................................8
Avista's WUI Risk Areas......................................................................................................................9
Wildfire Risk in Avista's Service Territory..........................................................................................9
Avista's Wildfire Resiliency Program Overview...............................................................................10
SituationalAwareness......................................................................................................................11
FireWeather Dashboard..................................................................................................................11
Wildfire Identification Cameras.......................................................................................................13
LocalWeather Stations....................................................................................................................16
Situational Awareness Budget & Targets ........................................................................................18
Grid Hardening & Inspections..........................................................................................................19
Distribution Grid Hardening.............................................................................................................20
WoodPole Inspection......................................................................................................................23
Transmission Grid Hardening...........................................................................................................25
Wood Pole Fire Resistant Mesh Wrap.............................................................................................27
Grid Hardening Budget &Targets....................................................................................................28
VegetationManagement.................................................................................................................29
VegetationOutages .........................................................................................................................30
RiskTree Definition..........................................................................................................................31
FireSafety Practices.........................................................................................................................31
Tools &Techniques for Inspection ..................................................................................................31
Avista's Vegetation Management Methodologies..........................................................................32
2

Distribution Vegetation Management Programs ............................................................................33
Transmission Vegetation Management Program............................................................................37
SafeTree Program ...........................................................................................................................39
Fuel Reduction Partnerships............................................................................................................39
MarketableTimber..........................................................................................................................40
Vegetation Management Budget &Targets....................................................................................40
Operations & Emergency Response ................................................................................................41
ExpeditedResponse.........................................................................................................................43
FireSafety Mode..............................................................................................................................44
Workforce Training and Practices....................................................................................................45
Operations & Response Budget &Targets......................................................................................46
Public Safety Power Shutoffs...........................................................................................................47
Wildfire Emergency Operations Plan (EOP).....................................................................................47
CustomerSupport............................................................................................................................49
PSPSCoordination............................................................................................................................51
PSPS-Specific Communications........................................................................................................54
2025 PSPS Activity............................................................................................................................56
Preparing for Wildfire Season..........................................................................................................57
PartnerForum..................................................................................................................................58
TabletopExercises ...........................................................................................................................58
PartnerPortal...................................................................................................................................59
Firefighters.......................................................................................................................................60
KeySafety Partners..........................................................................................................................61
Critical Service Providers..................................................................................................................62
OtherUtilities & Industry.................................................................................................................63
Neighbors.........................................................................................................................................63
OperationalExercises ......................................................................................................................64
3

General Wildfire Public Outreach and Engagement........................................................................66
Avista Wildfire Communications .....................................................................................................66
Wildfire Community Engagement Team .........................................................................................67
EquityAdvisory Group .....................................................................................................................68
Community Response for Vulnerable Populations (CRVP) Group...................................................69
TownHall Meetings .........................................................................................................................69
Community and Local Leaders.........................................................................................................70
Community Response Ambassadors ...............................................................................................71
CommunityEvents...........................................................................................................................71
Vulnerable Customer Outreach.......................................................................................................71
SpecializedOutreach .......................................................................................................................72
Lessons Learned & Plan Updates.....................................................................................................73
Communications..............................................................................................................................73
CustomerSupport............................................................................................................................74
Improving Tools &Technology ........................................................................................................75
New Programs & Strategies.............................................................................................................76
Expanding & Improving Existing Programs......................................................................................77
Operational Improvements .............................................................................................................77
Enhancing & Expanding Partnerships..............................................................................................78
VerifyingOur Programs....................................................................................................................78
Glossaryof Terms ............................................................................................................................79
4

List of Appendices
Appendix A
Commission Orders and Recommendations
Appendix B
State Budget &Targets
Appendix C
Third Party Undergrounding Report
Appendix D
Preventing & Mitigating Fires While Performing Avista Work
Appendix E
Avista Distribution Risk Tree Report
Appendix F
Public Safety Power Shut Off
5

STATEMENT FROM AVISTA EXECUTIVE MANAGEMENT
This is Avista's 5t" year of implementing the Wildfire Mitigation Plan (previously called Wildfire
Resiliency Plan). Avista's wildfire strategies are firmly rooted in our 136-year operating history and
represent the collective knowledge of Avista employees and fire agency professionals together with
assistance from peer utilities and other experts and, most importantly, engagement with customers.
This Wildfire Plan builds upon strategies originally developed in 2019 and aligns with the Company's
mission to provide safe, reliable, and affordable energy. Avista's Wildfire Plan is designed to reduce fire
risk associated with the operation of electric transmission and distribution facilities and reflects our
commitment to partner with customers, communities, and those who manage forest landscapes and
fight fires, as we all have a role to play in minimizing the risk of wildfire.
Heather Rosentrater, President and Chief Executive Officer (CEO)
9 4
Date: 11-20-2025
Wayne Manuel, Senior Vice President, Operations and Technology
e: - - 025
Josh DiLuciano, Vice President Energy Delivery
Date: 11-20-2025
Elizabeth Frederiksen, Director of Wildfire Resiliency and System Operations
Date: 11-20-2025
Matt Ugaldea, Manager of Wildfire Resiliency Program
AL
W14- Ga9a"4,el- Date: 11-20-2025
61

INTRODUCTION
Avista began development of a Wildfire Mitigation Plan in 2019 and published its first plan in June of
2020.The original plan was built upon Avista's operating history responding to and mitigating wildfire
activity, and we continue to do so five years later. Our 20261 Wildfire Mitigation Plan serves to reaffirm
Avista's commitment to reducing wildfire risk to communities and customers, as well as protecting the
infrastructure needed to serve our customers. This Plan also describes how the Company implements
the program elements to help protect public safety, being mindful of cost while maximizing benefits.
Wildfire Plan Goa is
The stated goals of Avista's Wildfire Mitigation Plan include:
1. Protecting Life and Property—To protect physical assets, property, and most importantly,
human lives, against the threat of wildfires; to recognize fire potential in our operating and
maintenance strategies; to take actions to reduce the risk of wildfire related to interaction of
Avista's system and the environment; and to minimize the impacts of wildfire to Avista's
infrastructure.
2. Emergency Preparedness—To recognize and react to wildfire as a recurring threat to
infrastructure, communities, and utility customers. To prepare and train for episodic wildfire
events and align operating practices with fire threat conditions to help mitigate wildfire risk.
3. Financial Protection—To mitigate the probability and consequence of direct financial costs and
liability associated with large scale fire events.
Guided by these goals, Avista's Wildfire Mitigation Plan is built on a foundation of proactive strategies.
The following section provides an overview of the key programs designed to implement these
strategies.
Wildfire Program Elements Overview
Avista's Wildfire Mitigation Plan takes a risk-based, regionally tailored approach to reducing wildfire
threats. Developed with input from internal experts and industry peers, the Plan builds on proven
practices while incorporating new technologies and strategies to address the unique challenges of our
service territory. By determining investment priorities based on information such as mitigation
effectiveness, cost-benefit analysis, and wildfire risk throughout the service territory the Plan ensures
that mitigation dollars are directed toward the most impactful actions, maximizing safety, and the
balance between cost and risk reduction.
We've enhanced existing programs like Vegetation Management and Grid Hardening, and introduced
new tools such as LiDAR, satellite imaging, and our Wildland Urban Interface (WUI) map to better
1 For the 2026 Wildfire Mitigation Plan,Avista is taking a forward-looking approach rather than focusing on past plans.While we have always maintained a
mitigation plan,there will not be a separate 2025 plan.
7

assess and manage risk. These efforts focus on high-risk areas, where 36% of our electric distribution
system is located.
Our wildfire-related investments are organized into four key program areas:
• Situational Awareness— Leveraging real-time data and predictive tools to monitor fire
conditions and support informed decision-making.
• Grid Hardening—Strengthening infrastructure to reduce the likelihood of ignition and improve
system resilience during wildfire events.
• Vegetation Management— Proactively identifying and mitigating vegetation risks near
powerlines using both field inspections and advanced remote sensing tools.
• Operations & Emergency Response— Enhancing readiness and coordination to respond
effectively to wildfire threats and protect communities.
Together, these programs form a comprehensive and proactive strategy to protect our customers,
communities, and infrastructure from the growing threat of wildfire.
Commission Orders and Recommendations
For detailed Commission Orders and Recommendations, please refer to Appendix A.
8

AVISTA'S WUI RISK AREAS
Wildfire Risk in A vista 15 Service Territory
Avista serves both
electric and gas
customers across Avista •cowl!
eastern Washington Washingtonsanapoirt
and northern Idaho, • • 'ho WASHINGTON Deem_ •l • Ow
Service
S�+okm. o,d'A�i�'t•
as well as natural gasTerritoryDavenport. •
•Kdlagq 4s
service only in parts •
St Manes
of southern and MONTANA
•Othello P'q"""•
eastern Oregon. In •V
g Coeur d'Alene-CDC �.
Colville-COC ■
addition, Avista owns Davenport-DAC
Deer Park-DPC ■ Lewis-dark•
a small portion of Grangeville-GRC ■ i",s
Kellogg-KEC ■ •crany.�n
electric transmission Lewis-Clark- LCC ■
Othello-OTC ■ IDAHO
and distribution Palouse-PAC OREGON
Sandpoint-SAC ■
infrastructure in St.Maries-SMC ■
western Montana.
Approximately 36% of Avista's electric distribution system is in areas of elevated wildfire risk. These
areas fall within the Wildland Urban Interface (WUI) zones where human development meets forested
land and where wildfire impacts are most likely. The WUI zone information is defined by state
agencies, such as Washington Department of Natural Resources (DNR).
To assess and manage wildfire risk for our distribution system, Avista uses a custom WUI model that
incorporates public and proprietary data, including vegetation, topography, weather, historical fire
activity, and infrastructure location. Risk levels are categorized into four tiers (WUI 0-3), ranging from
low to extreme, and are reviewed annually.
Approximately 62,600 customers (about 15% of Avista's electric customer base) reside in these higher-
risk zones.This model helps prioritize mitigation efforts such as grid hardening and vegetation
management, ensuring resources are focused where they can have the greatest impact.
Avista currently identifies risk on the transmission system by completing 100% annual inspection and
follow up remediations. Before wildfire season 2026, with the adoption of Avista's new risk modeling
system (ATS), the risk will be identified on both the transmission and distribution down to the structure
level.
9

Distribution Line Miles
State Low(0) Moderate(1)Miles Elevated(2) Extreme(3) WU12&3 Total Miles
Miles % Miles % Miles % Miles 10% 1 Miles I % I Miles 9/.
RK2,670 35% 780 10% 1,056 14% 652 8% 1,708 22% 5,158 67%
1,181 I is% 1 349 1 5% 1 419 5% 1 619 8% 1 1,017 11% 1 2,567 33%
3,851 50% 1 1,129 15% 1 1,474 19% 1 1,271 16% 1 2,745 1 36% 1 7,725 100%
Data presented is based on Avista's 2023 WUI area assessment.
Avista has provided our Avista's Wildiand Urban Interface Areas
WUI map technology
(most of it based on f
public information 's i
combined with internal
expertise) to otherWA
�t....
utilities, as there is a Ka Colville Sandpoint St Maries
desire to share "" -
ID
information, best °
practices, new tools, etc., " °°r ��°^v, ,.�,�
in the wildfire mitigation '"' �ronr rya131 T�.
1e' a, . e Lewiston&Clarkston
area where possible.
TeW 305 i�] 1]]i 1]2
o •� XVISTA
AVISTA'S WILDFIRE RESILIENCY PROGRAM OVERVIEW
Understanding where wildfire risk is greatest, specifically in the Wildland Urban Interface, allows Avista
to focus its mitigation efforts where they matter most. With this risk-based foundation in place, Avista
developed its first Wildfire Mitigation Plan in May 2020, following 18 months of collaborative planning,
analysis, and stakeholder engagement.
The wildfire program is designed to balance wildfire risk and cost of mitigation while also taking into
consideration system reliability impacts and ensuring that mitigation efforts don't disadvantage
communities that may be more rural, with lower income and limited firefighting resources. To better
serve these areas, Avista has integrated tools like the USDA's Wildfire Risk to Communities map, which
helps assess both the likelihood and potential impact of wildfire on people and property.
The following sections outline the key programs that make up Avista's Wildfire Mitigation Plan and
how they are being implemented to protect customers, communities, and critical infrastructure.
10

SITUATIONAL AWARENESS
Using Tools and Technology to Reduce Wildfire RiskSituational
Awarene
Avista's Situational Awareness program is designed to monitor wildfire '�"
risk in both the short and long term. We use a combination of tools to
identify high-risk areas and anticipate when conditions may require Fire WeatherDashboard
action, including our WUI map and Fire Weather Dashboard, and in Fire Risk Model
2026 our new Fire Risk Model. Local weather stations and fire WUl Map
detection cameras provide real-time insights into on-the-ground Fire Monitoring Cameras
Local Weather Stations
conditions, helping us respond quickly and effectively.
These technologies are fully integrated into our wildfire operations and
support informed decision-making throughout the fire season. We also coordinate with neighboring
utilities to stay aware of system changes, such as de-energization events, which could impact our
operations.
Fire Weather Dashboard
Monitoring Weather and Fire Risk
Launched in 2020, Avista's Fire Weather Dashboard has been a dynamic modeling tool that combines
National Weather Service forecasts with Avista's infrastructure data to assess wildfire risk across our
service territory. It generates a Fire Risk Index for each electric circuit, factoring in weather conditions
(e.g., wind, humidity, temperature), vegetation, topography, and historical system performance to
identify when and where wildfire risk is elevated.
The Dashboard is updated every two hours following the updated weather forecasts during fire season
and provides district-level and systemwide alerts, helping operators make informed decisions around
fire risk and reliability risk. It also tracks active fires and forecasts potential impacts to infrastructure
enabling proactive mitigation.
CEPT
9
N 0 • —
r � _
U � �a�acrx�
Forecast Temperature Wind Humidity Vegetation/Fuel Equipment Human Impact
(Sustained,gusts, Conditions (Condition&outage
direction) I Ilstory)
Fire Risk Index
Avista developed a Fire Risk Index (FRI) to support short-term forecasting of wildfire threat across its
service areas. The FRI integrates multiple data sources—including weather conditions, fuel types
(shrubs, trees, grasses), topography, community risk, historic summer outages, the Severe Fire Danger
Index (SFDI), Fire Preparedness, and the percentage of overhead spans in treed areas—into a single
11

numerical score ranging from 0 to 9.
• 0 represents very green, wet fuels with low wind and high humidity.
• 9 represents very dry fuels (live and dead), low humidity, and extreme wind speeds.
These scores are grouped into five index levels:
1. Green (Low)— FRI 0-4.0: Fire spread possible, minimal outage risk
2. Blue (Moderate)—FRI 4.1-5.4: Mixed risk profiles for outage and fire spread.
3. Yellow (High)—FRI 5.5-6.4: Elevated risk of outage and/or fire spread.
4. Orange (Very High)—FRI 6.5-6.9: Very high risk of outage and fire spread.
5. Red (Extreme)— FRI >_7.0: Extreme risk of both outage and fire spread.
The FRI has been used to support operational decision making, including activating extreme Fire Safety
Mode when the FRI reaches 5.5 or higher, or consideration of Public Safety Power Shutoffs (PSPS)
when the FRI reaches 7.0 or higher, alongside other situational factors.
Note: While the FRI has played a key role in wildfire risk assessment for the 2024 and 2025 seasons,
Avista is evolving its methodology and will transition to a new risk model, as covered in the following
section.
Evolving Risk Assessment: From Fire Risk Index to Advanced Modeling
While Avista's Fire Risk Index (FRI) has been a valuable, data-informed tool for wildfire risk assessment
during the 2024 and 2025 fire seasons, we are advancing our methodology in 2026.The FRI will be
replaced with a next-generation wildfire risk modeling framework that builds on its foundation and
incorporates additional data layers, such as asset fragility, ignition probability, fire consequence
modeling, and economic impact analysis.
This enhanced tool will support more precise, scenario-based decision-making for Fire Safety Mode
settings, Public Safety Power Shutoffs (PSPS), and other mitigation strategies. It will also help quantify
the cost-benefit analysis of various wildfire solutions, such as grid hardening and vegetation
management. The new model is currently in development and is expected to begin delivering insights
in early 2026. These enhancements will be reflected in the next version of the Wildfire Mitigation Plan.
12

11WWildfire Identification Cameras
Wildfire identification cameras are instrumental in quickly identifying
a fire start as well as its precise location. Early detection of ignition
increases the likelihood of timely containment and suppression of
WASHINGTON wildfires, minimizing any impacts to utility infrastructure and most
• Colville Mountain
• Lilienthal Mountain importantly, the communities we serve. This technology dispatches
• Scoop Mountain resources directly to the latitude and longitude of the smoke so
• Stanger Mountain firefighters do not have to search for the fire, saving valuable time.
• Saddle Mountain East
• Devils Gap Avista has contracted with Pano Al to install and monitor cameras in
• Krell Ridge
• Mount Spokane designated areas within our service territory.' Pano Al provides
• Steptoe camera surveillance, 24-hour monitoring, and computer machine
• Layton Hill learning to detect smoke, and potentially the start of a fire. These
• Coulee City cameras offer a full 360'view captured every two minutes. If the
• Teel Hill system detects a smoke plume, Pano staff are alerted. If the smoke
IDAHO plume is verified as a fire start, first responders and utilities are
• Gold Mountain notified and firefighters are sent directly to the site. Avista is
• Gold Cup Mountain partnering with professional firefighters to identify key sites in our
• Hoodoo Mountain service territory for camera installation. These agencies have full
access to the cameras in their jurisdictions. Avista dispatchers will be
notified as well to allow them to take action if it appears that our infrastructure may be impacted.
In 2024 Avista installed ten of these cameras; seven in Washington and three in Idaho, and, installed
another five cameras in Washington in 2025. In 2026, Avista is installing 10 additional cameras with
plans for more in subsequent years. Sites are
selected in high-risk areas, locations with clear
viewsheds, and factors such as accessibility and
power availability, with the goal of ensuring the
cameras can capture early fire detection and
provide comprehensive coverage up to ten miles
away. The cameras are located on existing towers
if possible, typically cell, communications, or
Avista towers based on providing an optimal view
of the area. Other areas require right-of-way
permitting or agreements with landowners. If
located on a non-Avista structure, Pano Al secures
a lease to enable installation. Other factors for
2 Pano Al is respected across the industry.Their customers including Portland General Electric,Puget Sound Energy,and Xcel Energy as well as fire
professionals such as the Washington DNR,the National Park Service,Idaho Dept.of Lands,Spokane Tribes,U.S.Forest Service,and over 1,600
additional agencies.https://www.pano.ai/fire-professionals
13

wildfire camera coverage include areas with dense vegetation or human activity that could lead to fire,
areas that have experienced past fire activity, and those with clear, 360-degree visibility to the
surrounding area (usually high points such as mountaintops or high ridges) without obstructions such
as trees or buildings. The cameras must be accessible for installation and maintenance.
Avista works with our agency partners, primarily the Washington Department of Natural Resources
(DNR) and the Idaho Department of Lands (IDL) to ensure that we are coordinating with their existing
or planned sites and that the new sites we are adding work effectively for them. Avista also
coordinates with the
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lric Distribution Eau and industry participants
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-3 obtain best coverage and
n Avista Vil K„..�k
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across large areas.
Avista and WA DNR Wildfire Cameras as of 2025
As mentioned, we share the camera view and alerts with them as well as many others. Currently we
have approximately 340 user accounts that can access Avista cameras, including agencies, government
personnel, dispatch centers, and emergency management organizations, enabling these entities to
effectively utilize our cameras. Pano Al continues to onboard Fire Response/Land Management
agencies to have access to our camera feeds.3 All of the Pano Al camera owners share access to their
camera feeds, enabling all of us to have a broad and comprehensive network. In 2025, Fire Response
and Land Management agencies viewed our cameras over 54,000 times.
3 Users include agencies across eastern Washington and Northern Idaho including the West Pend Oreille,Selkirk,Schweitzer,Northside,Colville and
Spokane Valley and County fire departments,the cities of Spokane and Colville,Washington DNR,county emergency management agencies and
dispatch centers,the U.S.Forest Service,and Tribal agencies(for now the Spokane and Colville Tribes).
14

Currently, the camera network covers 21% of our transmission lines and 51% of our distribution high
fire areas (WUI Tier 2 and Tier 3 areas). We prioritize high-risk zones that encompass numerous
customers and valuable assets. In 2024, Avista cameras alerted over 1,400 wildfire incidents, many of
which were first reported by the camera network.
In 2025, our cameras alerted to a fire near Priest River, Idaho, notifying firefighters who immediately
took action to prevent the fire from spreading. The early notification also allowed nearby residents to
evacuate safely. Additionally, we had an example in 2024 as well, where early detection technology
played a critical role in identifying a wildfire threat and enabling a swift response.
Piano in Action: Manley Creek Fire - May 2025
Pano alert provided visual intelligence on WUI fire in North Idaho
Temp:8O•1F RH:49% Wind Speed:5.8 mph
Gaa cu
Laclede / -
Detection • •10,
Piano alert time:2:43 PM PST Fire size at suppression:5 acres
Pano alerted 4 minutes after 911 Visual confirmation,triangulation,and Request Pano's actionable intelligence played an
Incident Zoom footage allowed for real-time important role allowing first responders and
Structure fire spread to wildland,multiple assessment and highlighted risk of spread in the emergency managers to evaluate evacuations
structure and vehicle involvement. shoulder season. and monitor fire spread.Contained at 5 acres.
Private and Confidential 1
In 2025, one of Avista's wildfire cameras in Northern Idaho notified first responders of afire start near Priest River, Idaho
15

Local Wea ther Sta tions
Weather stations enhance a utility's ability to know what the situation is
for a specific area. Weather stations can monitor relative humidity,
temperatures, wind speeds and gusts, all key factors in fire prediction, in
real time. Regional weather stations better inform operational decisions,
supplementing the information from the National Weather Service. The
granular data provided by a local weather station helps the utility gauge
fire behavior, allowing proactive response to a threat, especially as they
consider a Public Safety Power Shutoff. The stations can also monitor
conditions around powerlines and substations, keeping an eye on
increasing risk levels based on local weather behavior and notifying when
conditions have subsided so crews can begin restoration if needed.
Avista weather station in the
Avista is striving to achieve improved situational awareness of real-time Spokane Valley area
weather conditions within its service area and obtain site specific
forecasting of weather events. Strategic selection of sites to install weather stations, reliable and
proven sensors arrays, communication methods with the stations, maintenance and service of stations
(including access), and pertinent forecasting provide the information for an accurate risk model and
allow decisions to be made in a beneficial and timely manner. Consideration for station placement
considers, but is not limited to the following:
1. Areas with historically high wind conditions. Providing better data for areas where we have
routinely implemented elevated protection settings. The weather stations will help guide
when to elevate and when to return to normal operations. These real-time observations also
help ensure safety of our personnel who are patrolling and/or repairing the lines.
2. A specific pole or asset that allows us to monitor the highest winds, keeping in mind that the
higher the winds, the higher the risk. We also look for accessibility to a pole or asset for
installation and future maintenance of the weather station.
3. Fire risk for the area. We prioritized higher risk areas as defined by the Dashboard and our WUI
map. Better forecasting for these areas and real-time observations provide information
needed for better and more timely decisions.
4. Exposure that allows monitoring conditions. We looked for a specific site selected to obtain the
best data, free of obstructions that would limit or affect the data or communications.
5. Proximity to existing weather stations. We want to play a useful part in creating a more
complete network of weather data for all interested parties, to supplement not duplicate.
6. Rare event probability and consequences. We kept in mind gathering data in all areas, not just
the most likely to experience an issue. An unexpected or rare weather event can have a
significant impact regardless of wildfire risk tiers.
16

7. Communications. This includes coverage, right-of-way and permitting, impacts to local entities,
and availability of Avista communications or wireless coverage.
H •
Areas with Specific pole Fire risk for Exposure to Proximity to Rare event
historic high or asset to area defined monitorprobability
wind monitor by Avista's risk conditions Avista weather consequences Comms
conditions. highest wind modeling (not shieldedCoverage
or blocked) provided)
Criteria for selecting weather station locations
We have also contracted with meteorologists for site-specific forecasting during times of elevated fire
danger. Avista is continuing to work toward installation of local weather stations in key areas of our
service territory. We estimate completing installation of 60 weather stations in 2025. Weather station
location sites across our service territory were developed in combination with our weather station
provider, Weathernet. The Company also identified 20 additional sites in case any of the original sites
were not feasible. Site selection was based upon Avista's utility pole placement and Weathernet's
industry experience along with the elements described above. Avista will be adding an additional 78
weather stations in 2026. The data from these weather stations will be made available to the public
and other interested parties.
17

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Map of the first 50 proposed weather stations sites for installation in 2025. The brown lines indicate Avista's grid
Prior to having weather stations installed, Avista deployed several handheld Kestrel weather meters to
field personnel during the 2024 fire season in order to gather real-time weather information. Crews
were able to test the process of weather data collection and how it is relayed to Operations and key
personnel. These meters were used during Avista's 2024 PSPS event to provide weather updates from
the location of the outage to Operations, the Wildfire and PSPS teams, and to the Emergency
Operations team that was managing the PSPS event. In 2025 these handheld meters were used again
to monitor weather conditions near locations experiencing PSPS events. Based on the success of this
deployment, these meters will continue to be used in areas that do not have weather stations, and
more meters have been provided to line crews in additional areas of our service territory.
Situational A wareness Budget & Targets
For detailed budget and target information related to situational awareness programs, please refer to
Appendix B.
18

GRID HARDENING & INSPECTIONS
Grid
Strategies for Line Design, Inspection and Upgrade of LL Hardening
Equipment to Reduce Wildfire Risk
Powerline outages can result from uncontrollable events such as Distribution
storms, high winds, lightning, and vehicle collisions. However, o Overhead Grid Hardening
o Strategic ,_ , , ,
ing
upgrading conductors and equipment can significantly reduce o Covered Conductor
outage frequency and the risk of spark ignition, offering a cost-
.
effective mitigation strategy. o Steel Pole Conversions
• Wood Pole Wraps
Grid hardening represents the largest capital investment in o Inspections
Avista's Wildfire Mitigation Plan—approximately 90% of total
wildfire-related expenditures. While Avista has long-standing
programs for replacing poles, conductors, and equipment, these efforts have traditionally focused on
reliability and condition-based maintenance. Wildfire grid hardening shifts the focus toward reducing
spark ignition potential and enhancing system resilience during fire and other environmental stressors.
Hardening Strategies. Wildfire mitigation hardening strategies include:
• Rebuilding lines with hardened designs
• Using steel poles on transmission projects and high value distribution pole replacements
• Undergrounding select distribution segments
• Installing covered conductor
• Replacing wood crossarms with fiberglass
• Deploying automated protection devices (e.g., reclosers)
These upgrades improve system durability against high winds and fire exposure, directly supporting
customer safety and reliability.
19

Distribution Grid Hardening
Avista's Distribution Grid Hardening Distribution Outages by Cause 2009 to 2024
Program aims to reduce equipment Weather ,
Undetermined
failures, such as downed conductors and Tree
broken crossarms, particularly in high fire Public
Pole Fire V
risk areas identified by our WUI Tier map. Planned
Misc.
The new risk modeling will also include EquipmentUG Qj
capabilities to identify risk areas. Equipment sub
Equipment OH Wes— �
Company
Distribution lines experience line faults at Animal
a rate over 56 times higher than 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000
Number of Outages
transmission lines.4 With approximately
2,750 miles of distribution lines in high Historic distribution outages
fire threat areas, the scale of hardening is
significant. Since 2020, Avista has hardened about 200 miles of distribution lines annually.
Going forward, grid hardening efforts will focus on three key areas:
1. Undergrounding—selectively burying lines in strategic locations.
2. Covered conductor—installing insulated conductor in strategic locations.
3. Overhead upgrades— replacing wood crossarms with fiberglass, upgrading small conductors,
installing wildlife guards and lightning arrestors, using steel poles at critical spans, and replacing
obsolete equipment.
Additional measures include eliminating open wire secondary conductors, using wedge-connected
stirrups for stronger hot tap connections, and reinforcing/replacing spans over highways and rivers
with metal poles for added resilience.
These upgrades enhance system resilience, reduce spark ignition risk, and improve overall reliability for
customers.
31 Party Cost-BenefitAnalysis forAvista Undergrounding
In 2023, the Idaho Public Utilities Commission directed Avista to establish a formal process to evaluate
the undergrounding of distribution lines as part of wildfire mitigation efforts.
Avista initiated a formal process to evaluate undergrounding distribution lines for wildfire mitigation.
4 Based on Avista's Outage Management System data from 2009 to 2024.
20

This included establishing project criteria, a Cost Benefit
selection methodology, and conducting a Key Description
cost-benefit analysis for both completed and Components
future projects.
Loss of life and injuries to people&property as impacted by
Safety changes in wildfire risk associated with the undergrounding
Avista engaged Exponent Consulting, an project.
independent firm specializing in engineering Reliability Customers impacted by the project in terms of outage hours.
and economic analysis, to assess
Financial Direct costs of the project including both executing the project
undergrounding feasibility in high fire risk and continuing maintenance costs.
areas. Using Avista's Wildland Urban
Interface (WUI) map and internal prioritization Key areas of Exponent's evaluation
tools, Exponent analyzed segments of approximately 195 feeders.
Their evaluation focused on three key areas:
1. Safety— Economic value of reducing injury and loss of life.
2. Reliability— Financial impact of service outages.
3. Cost— Implementation, outage-related, and ongoing maintenance costs.
Exponent calculated benefit-cost ratios (BCRs) for each project, with values ranging from 0.06 to 11. A
BCR above 1 indicates benefits outweigh costs. While some projects scored below 1, the analysis
emphasized that even low-frequency events like wildfires can have catastrophic consequences,
warranting consideration beyond strict financial metrics.
Going forward, Avista will Calculation Values
incorporate scenario-based risk Ranges of outages with and without undergrounding lines.Use of
modeling through Aerospace Reliability Benefits historical outages specific to the feeder including customer counts
Technical Services (ATS). This model and Avista-specific customer interruption costs.
will include wildfire consequence Direct Costs Changes are estimated based on historical costs of outages
combined with the expected change in outage rate.
estimates (structures and acres
Calculated based on historical Avista data on maintenance costs for
burned, lives lost), ignition O&M Costs overhead&underground feeders combined with the length of the
probabilities, and pole fragility data. feeder to be undergrounded.
It also considers broader impacts Apportioned expected annual losses from FEMA's National Risk
Cost Reductions Index to utility-caused fires and to specific feeders based on wood
such as aesthetics, construction
pole and tree fall failure rates on that feeder.
risks, and economic effects on Project Costs Costs were provided to Avista including labor,civil construction,
customers. truck/lateral build,automation,and wreck out costs.
Together, these tools provide a comprehensive framework for prioritizing undergrounding projects
where cost effective and enhancing wildfire mitigation strategies across Avista's distribution system.
For additional details on Avista's third-party undergrounding project, refer to Appendix C.
21

A vistas Undergrounding Project
Avista selected a feeder located in southeast
Spokane, WA, within a WUI Tier 3 high-risk fire ` �
zone, to underground. This feeder is included
SPOKANE
on Avista's "risk list" and was transitioned into OI6N MAN
VALLEY
SPOK ANE
Fire Safety Mode multiple times in 2022 and
2023, underscoring its potential high-risk J J/
Apo ane
status. Serving approximately 190 customers Inbmafia, _ -
Atq,
across a semi-rural region, the feeder
J �comprises 11 miles of two- and three-phase
laterals. This project will allow us to evaluate 27
the feasibility of undergrounding as a wildfire -
mitigation tool.
t
m
Covered Conductor n
Faults are an inherent part of overhead distribution 2025 underground project feeder
systems, often caused by contact by trees, animals, or
other objects. These faults can result in arcing or downed
conductors, which may lead to spark events. Traditional
utility practice relies on bare wire and protection systems -
that detect and isolate faults by deenergizing circuits.
However, this reactive approach can still allow arcing
before isolation occurs, posing wildfire risks.
One strategy Avista is exploring to reduce spark event
potential is equipment upgrades such as covered conductor. covered conductor is heavier and more
Covered conductor is insulated to substantially reduce the robust than traditional bare wire.
likelihood of faults from external contact—reducing outages caused by vegetation, animals, and public
interference.
While covered conductor offers increased resiliency, it comes with trade-offs:
• Cost: Our studies have shown that overhead grid hardening treatments cost on average
$90,0000 per mile compared to covered conductor installations averaging$155,000 per mile.
• Weight & Wind Load: Heavier and larger diameter may require pole upgrades and can increase
wear.
• Operational Considerations: Occasional instances of energized wire on the ground without
outage detection.
22

Conductor Shield Inner Layer Outer Layer
Despite these challenges, a third-party study by
Exponent Consulting found that covered
conductor significantly reduces faults from
vegetation, animals, and public contact, and r
Conductor J
lowers phase-to-phase fault risk.
Covered conductor core components
A vista's Covered Conductor Project
Avista selected a 2.5-mile lateral section of a feeder near Springdale, Washington to install covered
conductor. Construction was completed in late fall of 2025. This is the first covered conductor project
in Avista's history. The team is learning a great deal from the experience, including the need for
extensive pole replacements as well as a
requirement for more poles as they must be placed
closer together, both due to the additional size and
weight of the wire. Through this cost and feasibility
study, we obtained a deeper understanding of the
unique challenges involved in constructing covered
conductor lines. This included learning about the Covered Conductor
need for specialized tools and equipment, updated Project Area
maintenance protocols, and potential supply chain
constraints. These insights have provided us with
more accurate data on actual cost per mile,
allowing for a clearer and more informed
evaluation of the cost-benefit relationship of
implementing covered conductor solutions based
2025 covered conductor project area
on real-world experience.
Wood Pole Inspection
Pole Inspection Process. Avista's Wood Pole Management (WPM) Program is designed to inspect
and maintain distribution and transmission assets with the primary goals of reducing fire risk,
improving safety and reliability, and minimizing unplanned customer Distribution Pole Count
outages.
59
Inspection Methods. The inspection process identifies issues such as: Idaho 84,4 85
Montana 85
• Insect, animal, lightning, or fire damage Washington 151,116
• Decay, mechanical damage, and equipment failure (e.g., leaking Total 235,659
transformers) Avista distribution pole count
• Unauthorized attachments, broken guy wires, grounding issues, by state
and soil concerns
23

Inspections include:
• Visual assessments of poles and attached equipment
• Intrusive testing, such as boring at or below groundline to detect decay, the leading cause of
pole failure
• Evaluation of associated components like crossarms, cutouts, transformers, grounds, and guy
wires
Distribution Scope and Cycle. Avista's Distribution WPM covers overhead
electric facilities in Washington, Idaho, and Montana. With around 230,000
distribution poles in the system (approximately 66% in WA, 34% in ID, <1% in
MT), the program operates on a 20-year cycle. To maintain this schedule,
- . around 11,400 poles (5%) are inspected annually, along with necessary follow-
up work.
In addition to poles, visual inspections include transformers, cutouts,
Wood Pole Inspection insulators, wildlife guards, lightning arrestors, crossarms, guying, and
grounding. Assets needing immediate attention are flagged for urgent
replacement; other work is completed when the full feeder is addressed. The program complies with
the National Electrical Safety Code (NESC) and Avista's internal standards.
Assets Identified for Replacement, and Daily Routine Operations. '
Pole replacements are based on inspection results. Attachments (e.g.,
transformers, cutouts, crossarms) are replaced if flagged during inspections,
even if the pole itself remains. Field crews also identify and address asset
issues outside the inspection cycle.
Prioritizing the Work. Work is prioritized based on:
• Risk level
• Customer impact
• WUI zone designation
• Inspection date Leaking transformer
Line crews, dispatchers, engineers, project coordinators, and area offices collaborate to assess and
schedule work. Imminent hazards, such as split crossarms, frayed conductors, or thin shell thickness,
are reported for immediate remediation.
24

Measuring Success. Avista focuses on wildfire-related metrics that reflect long-term system trends
rather than short-term or end-of-year results, which can be heavily influenced by variable factors—
most notably weather. Significant changes in
these metrics will take time, as they depend Distribution Related Outages
on the gradual replacement of thousands of 12,000
aging components, such as crossarms and 10,000
Qj
other distribution infrastructure. These t 8,000
programs are not designed for completion o'
p 6,000
within a single year but are ongoing efforts
that deliver continuous improvement, a 4,000
especially in grid hardening. 2,000
0
To evaluate the effectiveness of grid 2019 2020 2021 2022 2023 2024
hardening, Avista tracks outage-related
Distribution outages since the Wildfire Plan began in mid-2021
metrics. For example, reductions in animal-
related outages demonstrate the value of installing wildlife guards, as evidenced by downward trends
in our outage data.
Avista also tracks ignition events where, if a fire is observed when field personnel respond to an
outage, the field personnel will report to a Distribution Operator that a fire has occurred near our
facilities.This will trigger the Distribution Operator to open a screen in ADMS to note the location of
the incident to the nearest pole, the size of the fire in acres, if police or fire are present or on standby,
the severity of the damage, and the customers impacted. Previously the data was not captured as
accurately based on the ability of the outage management tool.
Transmission Grid Hardening
Since 2006, Avista has systematically replaced wood transmission poles with steel, primarily during
rebuilds or when poles are damaged or fail. Given that transmission poles are more vulnerable to fire
and significantly more expensive to replace, this effort now includes targeted wildfire mitigation
strategies:
• Steel Pole Replacement in high vegetation areas within WUI Tier 2 and 3 zones.
• Fire Mesh Wrapping of wood poles in low vegetation, high fire-risk Transmission Pole Count
areas like deserts and cropland.
Idaho 14,021
• Crossarm and Equipment Repairs identified through annual Montana 1,741
inspections. Washington 20,011
Total 35,773
Inspection Process and Schedule. Avista inspects nearly 38,000 Avista transmission pole
transmission poles on a 15-year cycle. Ground inspections assess pole count by state
integrity through visual checks and drilling to measure shell thickness. The
poles are annually inspected using aerial and drone-based inspections. Steel poles are inspected for
25

corrosion and foundation stability. Aerial inspections—conducted annually before fire season—identify
structural defects, vegetation risks, and other hazards. Drones are deployed for detailed follow-ups and
are being integrated into a more prescriptive inspection model.
LiDAR technology has been added to enhance vegetation risk detection and identify issues like
corroded hardware, ground profile changes, unauthorized attachments, and thermal anomalies.
Inspection Standards. Avista follows federal and industry standards, including NESC, FERC FAC-003-4,
and NERC FAC-501-WECC-2, which require annual inspection of 100% of the interconnected
transmission grid. Poles with less than 3" shell thickness are
further evaluated to see if the pole could be trussed. If
there isn't sufficient remaining wood where the pole is
banded, then it may be replaced. Those with at least 5" shell
^� thickness and no rot may be reinforced.
Issues found during inspections are categorized:
/ - • Urgent- Immediate repair or temporary fix.
j • Remediation Required-Scheduled repair within 12
months.
• Monitor- Non-critical, tracked for future action.
All findings are
logged in Avista's
GIS and asset
management
systems, feeding
Broken crossarm into a decision
matrix that
prioritizes repairs based on risk, WUI zone, customer impact,
and crew availability.
Measuring Success. Transmission outages have declined
since the Wildfire Mitigation Plan began in 2021, though
weather remains a major factor. Steel poles have proven Transmission pole inspection
effective in allowing fires to pass without destroying infrastructure, reducing outage duration and
improving resilience. Fire mesh wraps offer a cost-effective alternative in certain areas—approximately
$200 per pole versus $40,000-$100,000 for steel replacement.
26

Transmission Steel Pole Replacement
Since 2006, Avista has steadily replaced wood Transmission Related Outages
transmission poles with steel, and this effort 200
continues today. Currently, about 43% of Avista's 180
transmission poles are steel. A key objective of a o
the Wildfire Mitigation Plan is to accelerate this o 120
conversion in high fire-risk areas to improve 100
a 80
system resilience. i 60
40
20
Steel poles offer significant advantages: 0
2019 2020 2021 2022 2023 2024
• Fire Resistance—They withstand wildfire
exposure better than wood. Transmission outages since the Wildfire Plan began
• Enhanced Reliability— Less prone to failure from wind, lightning, insects, and birds.
• Structural Integrity—They resist cascading failures (domino effect) and reduce the risk of wire-
down ignitions.
Each year, Avista sets replacement targets based on budget and prioritizes poles in WUI Tier 2 and 3
zones, incorporating historical fire data and
topography into the decision-making rough
process. In areas with low vegetation, fire- transmission
resistant wraps may be a more cost- Spokone.Steel(on the left)
was ,,, ,
effective alternative to steel replacement. the right)was destroyed.
By layering fire risk, terrain, and vegetation
data, Avista ensures its steel pole
replacement budget is strategically
allocated to areas with the highest wildfire
vulnerability.
Wood Pole Fire Resistant Mesh Wrap
To protect transmission poles in fire-prone
grassland areas, Avista adopted a fire-resistant mesh wrap developed in collaboration with Southern
California Edison. The wrap uses a heat-activated chemical on a steel mesh substrate that expands
during a fire to seal and shield the pole.
27

This solution is deployed at the base of wood transmission poles in low-vegetation, high fire-risk areas
(WUI Tiers 2 and 3), where replacing poles with steel may not be cost-
effective. In contrast, steel poles are prioritized in areas with taller
vegetation and greater flame height potential.
Avista has found mesh wraps to be an effective and economical way to
protect infrastructure from ground-level fires while maintaining system I
reliability.
Grid Hardening Budget & Targets
Installing fire resistant
For detailed budget and target information related to Grid Hardening mesh wrap
programs, please refer to Appendix B.
28

VEGETATION MANAGEMENT
Practices and Tools to Reduce Vegetation Contact with Power Lines
Effective vegetation management is essential to maintaining safe
and reliable electric service and reducing wildfire risk. Avista has a Vegetation
long history of using industry-best practices, including cycle-based Management
tree trimming, risk tree removal, herbicide application, and the use
of tree growth inhibitors.
9 Risk Tree Inspection
9 Distribution
In recent years, Avista has expanded its vegetation management Satelliteon ,. . Imaging I
efforts to address wildfire risk more directly. These changes include: -- Program
. Fuel Reduction Partnerships
• Risk Tree Inspection Cycles: Annual inspections of
transmission lines as well as our distribution lines that are in
high fire risk areas.
• Risk Tree Removal: Trees identified as dead, declining, or found to be significantly structurally
defective are scheduled for removal.
• Advanced Technology: Use of LiDAR for high-precision transmission line assessments and
satellite imagery for distribution system monitoring, enabling early detection of clearance
issues and vegetation encroachment.
• Risk Classification: Trees are categorized by their potential to contact power lines—either
through grow-in (encroachment) or fall-in (collapse) and prioritized based on severity, location,
and proximity to infrastructure.
• Customer Outreach: Programs like the Safe Tree Program assist property owners in high-risk
areas with vegetation removal and replacement.
These enhancements reflect Avista's commitment to proactive wildfire mitigation and the integration
of data-driven decision-making into vegetation management strategies.
29

Vegetation Outages
Tree incidents on the distribution system far exceed those on the transmission system. In most
situations, transmission lines occupy a wider dedicated corridor right-of-way which affords the utility
greater authority to manage vegetation.
Also, transmission systems are regulated Avista Tree Related Outages
by federal agencies such as FERC and 700
NERC with prescriptive mandates for 600
vegetation. v 500
72
v 400
In the past 15 years, there have been 4
0 300
nearly 6,000 tree-related events on
E 200
Avista's electric network.5 Vegetation z' !TreeGrow-In,
contacts during periods of moderate to 100
high winds represent a significant o
contributor to the fire risk profile. 1
2011 2013 2015 2017 2019 2021 2023
Avista's tree-related outages for distribution and transmission
Avista's Vegetation Management Program
is highly effective and commensurate with peer utilities in the region. A third party evaluation of our
program found it "best in class" as described below. Despite encountering significantly higher levels of
tree mortality across Avista's service territory—more than double the initial projections based on
previous years—Avista has approached this challenge with notable effectiveness. In 2024, we removed
17,449 risk trees on the distribution and transmission systems as we continue to reduce the backlog of
risk trees across our system.
Reducing the
number of tree falls
<•
is an important
L
component of !'
Avista's Wildfire
Mitigation Plan and
positively impacts
both wildfire risk �< j
reduction and
customer service
and reliability.
Drought, disease, These photos, taken 4 months apart,show the rapid impact of an insect infestation
and insects have
weakened trees in our service territory. Insects such as the pine bark beetle and spruce moth have
5 Avista Outage Management System,2009-2024 dataset.This includes 5,872 incidents on the distribution system,71 on the transmission system.
30

emerged as significant contributors to tree mortality and continue to increase the number of risk trees
in our service territory. Forest health was made more dire by the historic drought of 2021 but also
reflects increased levels of insect activity combined with human activity, all leading to higher levels of
tree mortality than expected. In fact, the USDA anticipates "substantial tree mortality from insects and
diseases through 2027.116
Risk Tree Definition
At Avista, all risk trees with the potential of imminent fall-in hazard to the energized facilities are
removed to eliminate potential for spark ignition events or outages. A risk tree is defined as visibly
dead, declining, or found to be significantly structurally defective which could lead to falling into the
conductor as defined in ANSI A300 (Part 9)-2017.'
Assessments conform to level 1 standards as performed
from center of corridor, using ground-based or vehicle-based 1
patrols.
"Cycle Busters." Any tree that is making contact with the
conductor is mitigated immediately. Any fast growing
species that is growing at a rate faster than the 5-year
pruning cycle and is encroaching the conductors beyond an
acceptable clearance within those 5 years is defined as a Example of a tree fall-in contacting power line
"cycle buster". All reasonable efforts are made to remove
such trees as quickly as practicable.
Fire Sa fety Pra ctices
Avista follows Washington Industrial Fire Precaution Levels and Idaho Fire Restrictions rules and
requirements. Avista contract vegetation crews and in-house construction crews are compliant with all
aspects of these rules. To review further details about preventing and mitigating fires while performing
Avista work, please refer to Appendix D.
Tools & Techniques for Inspection
Avista's Wildfire Plan added to the traditional boots-on-the-ground, aerial, and vehicle-based
vegetation inspections with digital data collection methodologies. Specifically, utilizing LiDAR for the
transmission system and satellite imaging for the less-linear layout of the distribution system. In
addition, drones have been used for risk tree inspections over the last two years in areas that are
difficult to access on foot and/or areas that present safety concerns to inspectors.' In 2024 the use of
6"Forest Health Summary for the Pacific Northwest Region 2022:USDA Forest Service:Forest Health Protection,Oregon Department of Forestry,and
Washington Department of Natural Resources,July 11,2022,Forest Health Summary for the Pacific Northwest Region 2022(arcgis.com)
7 https://treecareindustryassociation.org/business-supporVansi-a300-standards/part-9-tree-risk-assessment-a-tree-failure/
a The Clearwater River canyon between Grangeville and Elk City.
31

an Avista drone (piloted by an Avista drone pilot) and a contracted arborist/inspector completed
inspections. In 2025 the contractor is using their own drone to complete the inspection, creating a
more efficient process. Avista is also exploring LiDAR captured by our internal drone team for use in
vegetation management, but it has only been demonstrated in test cases so far and is not operational
yet.
Avista's ftetation Management Methodologies
Avista's Vegetation Management Program incorporates four primary methodologies:
1. Routine Cycle Maintenance: The goal with this program is to inspect the entire distribution
system on a 5-year cycle, focusing on trimming practices specific to individual site and tree
species. Routine Cycle Maintenance also removes young trees/brush or established trees that
grow too fast to remain within the 5 year cycle.
2. Risk Tree Mitigation: Trees that are dead,
declining, or found to be significantly t
structurally defective are identified as Risk
trees. Avista employes a one-year inspection
Y
cycle to identify risk trees on 100% areas that '
fall within certain selection criteria. Risk trees 1�
found through inspection are mitigated prior to
the following fire season. Any tree that is
deemed to be an immediate threat of failure i
and any vegetation that is identified in contact
l
or potentially making contact under load during
inspection is called out and managed within an
A branch spanning two conductor segments for
escalated timeframe, depending on circumstance. a sufficient period of time may ignite the branch
3. Unplanned Work: This is ad hoc work that requires and also may produce high-energy, high-
off-cycle mitigation outside of Risk Tree or Routine temperature arc
Cycle Maintenance Programs. These requests occur when a lineman, customer, or tree crew
identifies and reports a tree that needs mitigation. They are prioritized appropriately and
assigned to tree crews. This work can include storm work, some grid hardening-related
vegetation work, and safety trims.
4. Right of Way Clearing: This includes physical removal of brush and undergrowth within the
right-of-way using heavy mowing equipment and the selective application of herbicides. This
practice is more prevalent on the Transmission system, with a typical herbicide treatment
applied on a 6-10 year cycle.
The Distribution and Transmission systems each have individualized inspection, and mitigation plans as
well as schedules. These are described in more detail below.
32

Note: The Idaho Commission asked if we considered "vegetation management recommendations by
other federal, state, and county agencies into its standards." While we have not incorporated the
standards of other programs into our own at this time, we maintain a collaborative approach across all
aspects of the Plan and value ongoing feedback and suggestions. However, vegetation management
for utilities differs from general practices primarily due to the need for safety, reliability, and
compliance with utility-specific regulations. Avista's vegetation management practices are based on
established industry standards: ANSI A300 (Part 9)-2017 Tree Risk Assessment- a. Tree Failure as well
as NERC vegetation management regulations specific to electric utility transmission to protect the
integrity of the grid.9
In addition, in June of 2023, the Idaho Public Utilities Commission (IPUC) requested that Avista engage
a third party to conduct a study of the most efficient vegetation management cycle for the service
territory. This study was completed in May of 2024 and found that Avista maintains a reasonable and
responsible approach that is aligned with "best-in-class" vegetation programs of other major utilities,
and that that Avista's annual-cycle approach to managing utility-related wildfire risk is an effective
strategy. This study can be found in Appendix A.
Distribution Vegetation Management Programs
Routine Cycle Maintenance
The Routine Cycle Maintenance portion of Avista's Vegetation Management program inspects 100% of
the service territory over a five-year period, or approximately 20% of the distribution system annually.
This work can include program maintenance, customer service requests, work requested by local
offices, a tree replacement program (the Safe Tree Program), and can include risk tree inspection and
mitigation.
During our Routine Cycle Maintenance, we maintain five feet of clearance for distribution lines (based
on tree type and the site). When tree crews identify a risk tree during the routine inspections they pull
it out of the routine schedule and prioritize it to be addressed as risk. Avista endeavors to mitigation
risk trees no later than July 1 of the following year (the start of fire season).
This program will continue to operate as it was designed, working in conjunction with Risk Tree
Program that resulted from implementation of the Wildfire Plan.
Risk Tree
In 2020, the Wildfire Risk Tree Program was split from the Routine Cycle Maintenance Program and
given its own budget and scope of work. Each of these programs have different focuses but work
synergistically to maintain all trees impacting Avista system.
9 FERC Reliability Standard FAC-003-4,Template-Standard(Results Based)(nerc.com)
33

The Risk Tree Program is a major focus and O&M expenditure category in the Wildfire Plan. It added
the following elements to our already existing Vegetation Management Program:
• Annual Risk tree inspections across 100% of the high fire risk areas of the distribution system, as
well as additional rural areas, with the goal of mitigating risk trees prior to July 1 of the next
wildfire season. This consists of ground-based visual inspection of approximately 6,546 miles or
83.5% of the distribution system.
• Fuel Reduction Partnerships with external parties such as the Idaho Dept. of Lands and
Washington Dept. of Natural Resources to reduce fuels/vegetation on their properties near our
facilities.
• Creation of a customer-based Safe Tree Program to remove and/or replace trees on customer
property in danger of contacting powerlines.
Inspection Practices. Risk tree inspections are
typically conducted on an ongoing basis
throughout the year. The timing of inspection in a
specific place on the system will differ from year to year as the Company seeks to balance many
contributing factors impacting inspection and/or
the ability to perform subsequent tree work. These
factors include snow in remote and mountainous •,
areas, weight limits imposed on area roadways, ._
Industrial Fire Precaution Level (IFPL) shutdowns,10 •
and labor constraints impacting the number of
inspectors available.
Inspection Standards. Avista's distribution Tree trimming in action
inspections are regulated by ANSI A300 (Part 9)-2017 Tree Risk Assessment - a. Tree Failure."
Assessments conform to level 1 standards as performed from the center of the corridor using ground-
based patrols. WUI Tier Weight applied Sample calculation CDA_R_P4(WUI%)x weight
3 10 0.229 x 10=2.29
Prioritizing the 2 5 0.655 x 5=3.275
1 1 0.009 x 1=0.009
Work. Risk tree work overall risk score 5.574
is prioritized by WUI
ranking and assigned for mitigation. A weight is applied to each of the WUI tier levels to ensure that
Tier 3 areas are placed at higher priority levels for mitigation than areas with lower risk. The table
10 In Washington,Industrial Fire Precaution Levels(IFPL)are used to close areas of forest in order to reduce wildfire risk.By law it applies to industrial
forest workers,including utilities,on over 13 million acres of forestland in the state.https://www.dnr.wa.gov/ifpl
11 ANSI A300 Standards,ANSI A300 Tree Care Standards-Tree Care Industry Association,LLC.Both print and digital copies of these standards are
available for purchase.
34

above demonstrates how the overall risk weighting score is calculated.
Maintenance, Repairs, and Operations. Vegetation inspection is
satisfactorily completed when all identified risk trees are captured in
the appropriate database, notification is made from the inspection
contractor to Avista, and the workplan is updated.
Actions required prior to mitigation include notification to :�;:x
customers in advance of work, obtaining necessary permits to
perform work, organizing any specialized equipment, and/or
arranging for site-specific requirements to perform work, and
ultimately pruning or removal of vegetation according to plans and �.
4�
ANSI guidelines. Outside of the programmatic inspection and
mitigation, there are also trees identified by inspectors, employees,
and customers that pose imminent threats to energized facilities.
These trees are mitigated based on the estimated imminence of :" !�€ �
failure, sometimes within a matter of hours. Execution of the Risk tree marked for removal
mitigation schedule is subject to various constraints including regional
accessibility due to weather, regional vehicle weight restrictions, regional state restrictions, and the
time it takes to obtain required permits to perform the work. There are also other circumstances
outside of the company's control such as property owner refusal and governmental and tribal
permitting. 12
During the removal of risk trees, precautions are taken to avoid damage to adjacent standing timber or
other property. Dead trees are felled and left. Live risk trees are felled and limbed flush. Disposal of the
trees is in accordance with the general specifications or landowner agreement. Care is taken to
mitigate fire hazards posed by risk trees, including thorough dicing of debris, or moving debris to
another location. When risk assessments are made, the risks associated with wildland fires are
factored in regardless of the current fire conditions.
Measurable Targets and Goals. Avista tracks miles of inspections completed as well as remediation
activities. For distribution satellite data collection, Avista tracks inspection miles completed. Note that
we do not set goals for risk trees removed, as the number is dependent upon factors outside of the
Company's control which can vary widely from year to year, for example drought, insect damage, or
disease. The resulting variance in work required and associated cost is managed through each
Commission-approved Wildfire Expense Balancing Account, which provides flexibility for unexpected
expenditures such as a greater number of risk trees removed than anticipated. For this category we
12 Washington State experienced several strong windstorms in 2024,including the November bomb cycle on the west side of the state,which is
considered the worst windstorm in Washington in over 60 years."Washington windstorm among the worst in 60 years,"Axios News Seattle,November 25,
2024,https://www.axios.com/local/seattle/2024/11/25/bomb-cyclone-historic-windstorm-washington-pnw-2024
35

track actual number of removals.
Measuring Success. A key performance measure of the Wildfire Plan is reducing the number of tree
incidents Avista experiences over the long term. Tree contacts with powerlines are categorized as
either grow-in risk (encroachment into lines) or fall-in risk, with dead, dying, and diseased trees
naturally more likely to fall into electric lines than live green trees. Our historical outage data indicates
that in our service territory, trees fall into electric distribution lines about five times more often than
they grow into them. There are far fewer tree incidents with transmission lines than distribution lines,
largely because right-of-way corridors are often better defined for transmission lines compared to
those for the distribution system. Over time we have a decline in tree-related outages. Reducing the
number of tree falls is an important component of Avista's Wildfire Mitigation Plan and positively
impacts both wildfire risk reduction and customer service and reliability.
For further details regarding the Distribution Risk Tree
Program please see Appendix E. Distribution Tree Fal[Ins and Grow-Ins
600
Distribution Satellite Imaging 500
For the distribution system, we began incorporating a 400
satellite-based methodology which allows for a 300
system-wide approach rather than conventional E zoo
corridor collection. Satellite imaging aligns well with
distribution topologies, as it works very efficiently for 100
the trunk-and-lateral, non-linear configuration of the 0
distribution system, which may lack well-defined 2020 2021 2022 2023 2024
flyable corridors. Satellite acquisition allows collection Tree-Falllns UTreeGrow-Ins
over a broad area both in urban and rural areas. This Distribution tree events over time
system uses high resolution satellite imagery acquired
once per year and pairs this information with computer-based machine learning algorithms to assess
the risk of both tree encroachment (grow-in) and risk tree risks (fall-in). Although Avista continues to
test the feasibility of utilizing distribution satellite imagery for vegetation management, the results do
not currently drive our work plans or areas of work specifically at this time.
36

Transmission Vegetation Management Program
Avista's Wildfire Plan did not alter the thorough vegetation maintenance practices on the transmission
system but did add LiDAR surveys to aid with inspections. LiDAR inspections can specifically identify
and measure vegetation type and precise distance from conductors as well as fall-in potential.
LiDAR aids in focusing tree work where it will provide the most value and protection. Transmission
Engineering is also using LiDAR images to help identify maintenance issues or problems that are not
easily seen with visual inspections.
Avista operates approximately 700 miles of 230 kV and 1,600 miles of 115 kV transmission lines
throughout eastern Washington and northern Idaho.13 Unlike the distribution system, there is no
rural/non-rural distinction for transmission risk tree inspection, and so with a combination of ground-
based, aerial, and LiDAR inspection, 100% of Avista's transmission system is inspected for risk trees
each year, equating to 2,270 miles of the transmission grid. Line inspection schedules are determined
annually and set on a flexible schedule allowing for availability of helicopters, weather, access,
condition of the right-of-way, length between inspections cycles, anticipated growth of vegetation, and
reliability information.
Aerial Inspections. Aerial inspections are used to assess vegetation conditions both within and
beyond the right-of-way (ROW). These inspections help identify:
• Dead or dying trees
• Leaning trees
• Vegetation encroaching on conductors from the sides or underneath, especially in deep draws
where large trees remain below the wires
• Areas where line sag and sway may affect clearance
Aerial inspections are especially valuable in regions such as fields, scablands, and canyon lands that are
difficult to access or observe from the ground. They also provide a broader landscape view, particularly
in areas with sparse tree cover.
During aerial inspections, additional observations are made, including:
• Recent logging activity
• Wildfire-affected areas
• Disease outbreaks
• Unauthorized attachments or structures
• Tree mortality
• Road access conditions
3 2024 Avista Quick Facts,365756ed-8fd4-48f4-9abe-e79ef78c730b(avistacorp.com)We also part owners of about 500 miles of 500 kV lines out of
Colstrip in Montana but are not responsible for maintenance of inspection of these lines.
37

When potential issues are identified from the air, a follow-up ground inspection is automatically
initiated. In some cases, landowners are notified as a courtesy prior to aerial or ground inspections.
Ground Inspections. Ground inspections are essential for identifying overall vegetation
characteristics and condition on and adjacent to the ROW. This includes observing vegetation
clearances to conductor, vegetation height on the ROW, and identifying hazard trees. Tree
assessments consider multiple factors, including:
• Species and condition
• Proximity to transmission lines
• Structural integrity and anticipated growth
• Movement and failure characteristics
• Historical failure data in the area
• Terrain and accessibility
• Span location and line voltage
• Line construction, wire sag, and sway
• Fire risk and easement/permit details
In forested areas, especially along transmission ROWS, ground inspections are the primary inspection
method. They allow for detailed observation of trees both within and along the edges of the ROW,
enabling more accurate identification of potential issues.
UDAR Inspections. LiDAR technology provides precise data on vegetation type and proximity to
conductors, including fall-in potential. It can detect clearance issues that may not be visible through
traditional methods and pinpoints exact locations of concern.Tree health can also be assessed by
LiDAR, which can detect stressed trees.
Avista has been using LiDAR technology to inspect transmission lines since 2020. While calibration with
human observations is ongoing, UDAR is rapidly becoming an industry standard. It enables a
comprehensive vegetation record and supports the development of future work plans.
Currently, LiDAR analytics are used to prioritize tree work where it offers the greatest risk reduction
and system protection. By combining digital data with machine learning algorithms, we are shifting
toward a risk-based treatment approach rather than relying solely on routine maintenance cycles.
Avista also leverages imagery to identify maintenance needs and diagnose specific issues. Additionally,
LiDAR data supports refinement of our Wildland-Urban Interface (WUI) maps by distinguishing
between high canopy and low vegetation areas. This information informs transmission resiliency
planning, including decisions between steel replacement and fire mesh wrap strategies.
38

Safe Tree Program
Avista's Safe Tree Program proactively RIGHT TREE, RIGHT PLACE!
Before planting new trees to improve the look of your yard,you wl I I need to keep
works with customers in high fire-risk Pruning Zone
Tees and shrubs will
areas to remove tall, non-compatible .,m�10'�;"°y�°
..mead power eves
35 fl h h h he to help prevent
trees near power lines and replace $-°-�-=• 35n^^-�,le== ; «d�pP.
at least 50 ft away; 25-50 ft away:
them with low-growing species, at no
cost to the customer. Since launching in
2022, the program has expanded across S�, ..........'
t
EEII•,L. i 10.25 ft awour service territory, with strong
t Keep Clewcustomer engagement through - •. - Kap.msoundm•erclear fromabebuctiom.4
MyAvista.com. Most customers opt for tp<e bey
and Gatelyremoval without replacement helpingClearance Zone i Large Tree Zone: Medium Tree Zone: Low Tree Zo
Trees and shrubs should be Plant largg trees Plant medium trees h is bestnotto plant in this area.
��lantek6tl at least 10 h awe over 35 R wnen mature)ft at (over 2east5 ft when away,
d ou do,plant only I:-f�S{row,n.
reduce long-term maintenance and tra s(orm'sh" [etl y oeehead power lines. oIrhead5poweft rl nes. Iessthanees tlt5k'hentmatre nt
wildfire risk. Over 4,000 risk trees have
been removed though the program to date.
Fuel Reduction Partnerships
Avista believes that partnerships with external entities are essential to effective wildfire prevention
and mitigation. We work with professional firefighting agencies at every level—from local to national—
to strengthen relationships through joint training, simulation exercises, emergency operations, and
shared efforts to promote fire-adapted communities. We
also incorporate partner feedback into our strategies and
provide funding to state and local agencies to reduce fuels 2025 Projects
near our facilities. This program, known as Fuel Reduction
• City of Spokane:reduced fuels
Partnerships, has been active since 2022.
on 25 acres
• Town of Malden:provided
A key focus of this program is supporting our wildfire allies— grazing goats on Avista Rows
primarily state, county, and Tribal agencies—in reducing to reduce fuels naturally on
about 25 acres
fuels that contribute to catastrophic wildfires. For example, . WA DNR:treated 384 acres on
the Washington Department of Natural Resources (DNR) is Avista customer properties
implementing a 20-year forest health plan across 2.7 million • Bonner County, Idaho:treated
54.5 acres
acres in central and eastern Washington, targeting areas
impacted by beetle kill and other forest health issues. Avista
partners with agencies such as the Washington DNR, Idaho
Department of Lands, the Nez Perce Tribe, and local fire districts to fund forest thinning and brush
reduction near our infrastructure. These efforts help reduce wildfire severity and fill funding gaps faced
by these agencies.
39

In Idaho, several communities served by Avista are classified as at risk of wildfire. We collaborate with
the State to support fuel reduction in these areas, where treatment costs are higher due to denser
vegetation requiring more mechanical intervention. One example is our support for Bonner County's
BonFire Program, which provides technical expertise and labor to help landowners reduce fuels around
their homes. In 2025, we Agency Agreement
supported funding for Washington Dept.of Natural Resources $look/year through 2032
treatment of 54.5 acres Bonner County,Idaho $160,000(one year only)
in Bonner County. These Spokane City,Washington $25k/year through 2026
Malden,Washington Goat grazing,not to exceed$10k total through 2025
efforts not only protect Latah County Conservation District,Idaho Not to exceed$150k/good forfive years
local communities but
also foster new partnerships with fire agencies across Idaho.
In Washington, our projects have included fuel reduction in Spokane's Dishman-Mica Hills Natural Area
and innovative approaches like using grazing goats to manage vegetation in the town of Malden. These
initiatives continue to strengthen our relationships with key partners and contribute to broader
wildfire mitigation goals.
Fuel Redudion Partnerships o.ls 2i26 2027 2028
Washington Acres PerYear 1 150 1 150 1 150
Idaho Acres Per Year 1 60 1 60 1 60
Fuel reduction goals
Marketable Timber
We do not currently have any agreements or rules with timber companies that inform us how
payments at fair market value will be made for the removal of live, merchantable timber. However, it is
our practice to notify all landowners of the need to remove live trees prior to removal. Merchantable
timber on private land generally belongs to the landowner. It is cut and left in whole tree lengths along
the right-of-way. Whether payment is required, how the value would be determined, and the amount
owed would all be borne out of our conversation with the landowner or their representative when we
seek permission to remove the live tree. On agency property (USFS, BLM, state, and Tribal lands)
approvals are also needed, and timber is appraised and paid for prior to cutting. If the logs are
purchased by Avista, they will either be hauled to a sawmill or left on site. Rules and regulations
pertaining to Forest Practice Acts in the States of Idaho, Montana, and Washington shall be followed
when harvesting timber from rights-of-ways.
Vegetation Management Budget & Targets
For detailed budget and target information related to Vegetation Management programs, please refer
to Appendix B.
40

OPERATIONS & EMERGENCY RESPONSE
Protective Devices & Operational Practices to Reduce Risk
Operations
Wildfire risk is influenced by equipment failures,vegetation Response
contact, wind, snow, and lightning—all of which can cause line - -
faults and disrupt electric service. To mitigate these risks, Avista
employs a combination of infrastructure upgrades and operational • Automation
practices designed to reduce fault frequency and impact. • Expedited Response
• Fire Safety Mode
Historically, our programs have focused on reliability and customer Public Safety Power
Shutoffs
service. With the implementation of our Wildfire Plan, we've Training/Cross-Training
expanded these efforts to include wildfire risk reduction. This Emergency Operations
includes installing or upgrading midline reclosers and substation Plan
breakers to enable Fire Safety Mode protection settings on circuits
in elevated fire risk areas. These devices provide greater control
and automation over our distribution protection systems, helping prevent spark events.
Flexible Infrastructure & Remote Operations. Avista utilizes flexible infrastructure such as
automatic reclosers and remote-controlled devices to support wildfire mitigation. These technologies
allow us to:
• Monitor and control distribution equipment remotely.
• Adjust protection settings dynamically based on fire risk.
• Disable reclosing or de-energize lines in extreme conditions, following established procedures.
Centralized data systems like SCADA provide real-time visibility into the power system, enabling
operators to respond quickly to changing conditions and implement protective measures.
Fire Safety Mode & Expediated Response.When fire risk is elevated, Avista activates Fire Safety
Mode operations, modifying distribution protection settings to reduce the fault current exposure,
ultimately reducing the chance of equipment-related ignition. In severe cases, we may implement
Public Safety Power Shutoffs (PSPS) to proactively de-energize lines.
We also deploy Expedited Response protocols during fire season, dispatching professional firefighters
to the site of any transmission outage to verify that no spark or fire has occurred.
Partnerships & Communication. Effective wildfire response depends on strong partnerships. Avista
collaborates with organizations such as the Red Cross, Washington DNR, IDL, and local firefighting
agencies to coordinate preparedness and response efforts. Our plan also includes a robust
communication strategy to keep stakeholders informed during wildfire events.
41

A utoma tion
Avista's automation strategy focuses
on enabling remote monitoring and
Circuit Recloser added at
control of key protection devices Distribution this location to enable FSM
Main Trunk Line
across the system and within
substations—especially in areas with Midline Circuit
elevated wildfire risk. Automation Recloser
equipment acts as "eyes" on critical ---- Non-WUI
infrastructure, allowing operators to substation circuit
Recloser Zone
respond quickly to changing weather
conditions that could increase fire
danger. Example ofAvista's use of a recloser
As part of our Wildfire Mitigation Plan, we have installed SO midline circuit reclosers throughout our
system in both urban and rural settings to provide the capability of deploying Fire Safety Mode
settings, isolating higher risk segments of feeders, as well as isolating faults. Many existing reclosers
lack remote capabilities, requiring manual intervention that can delay response by hours.
We are also upgrading substations in high-risk areas to support full automation. These upgrades vary
widely depending on existing infrastructure. Some substations may need only minor hardware
updates, while others require major installations like SCADA systems or new fiber/T1 lines. The scope
and cost of each upgrade depend on factors such as the number of connected lines, existing
communications infrastructure, and equipment condition. This multi-year effort is expected to
continue.
42

Expedited Response
During the development of Avista's Wildfire Mitigation Plan, we collaborated with fire professionals—
including Washington DNR, IDL, and Spokane County Fire Districts—to shape our strategies. One key
outcome of these discussions was the creation of the Expedited Response protocol.
Under this approach,
during fire season, Avista's 2022 �+ 2023 ..
System Operators initiate a L u 100Miks o za s. +oorui�
call, to the appropriate ' '
agency, whenever a
transmission fault occurs. 1 Montana Montana
This triggers the dispatch Wash' Was
of professional firefighters
to the fault location. The41
goal is rapid response: if a ,'�
fault results in a spark
event and ignites a fire, Oregon _ Oregon
trained crews can engage
faster, helping contain the fire Avista's Expedited Response Agreements started in Spokane County in 2022 and
before it spreads. now cover nearly our entire service territory
In 2022, Avista signed a Memorandum of Understanding with Spokane County Fire Department to pilot
this program. Following its success, the initiative expanded across our service territory. By 2023, Avista
had formal agreements with IDL, the U.S. Forest Service, and
Washington DNR to respond to transmission-level outages during
fire season in both Idaho and Washington.
These agreements allow our System Operators to request
professional fire response during trip/reclose events when fire
risk is elevated. A successful simulation with Washington DNR in
June 2023 confirmed the effectiveness of the protocol—fire crews
responded exactly as planned. These agreements are open-ended
and cost-free to Avista.
Firefighters respond to a pole fire
With most of our transmission system now covered under
expedited response agreements, we've added a critical layer of protection for our infrastructure and
customers. To date, no fires have been found during these response activations, and we plan to
continue using this strategy as part of our long-term wildfire mitigation efforts.
43

Fire Safety Mode
Electric faults—caused by equipment failure, vegetation contact, or severe weather—can interrupt
service and pose wildfire risks due to the energy released before protective devices isolate the fault.
Utilities typically use automatic reclosing to isolate faults, reduce safety risks from faulted conditions
and potentially restore service quickly after temporary faults. However, in high fire risk areas, repeated
reclosing can increase the chance of spark events. To address this, Avista developed Fire Safety Mode
(FSM)—a targeted strategy to reduce wildfire ignition risk by adjusting distribution protection settings
to better match the wildfire risk conditions to appropriately limit the fault energy that could occur with
an electric fault.
Evolution of FSM. Avista began limiting reclosing on at-risk circuits during fire season in the early
2000s under a program called "Dry Land Mode." In 2020, Fire Safety Mode (FSM) was created to utilize
group setting capabilities with the protective relay to deploy protection setting changes to align with
the current wildfire risk conditions to more appropriately limit the fault current that could be
experienced. FSM includes multiple protection levels based on fire risk, determined by Avista's Fire
Weather Dashboard and its Fire Risk Index.
How FSM Works. FSM is activated based on weather forecasts, drought conditions, wildfire activity,
as well as state agencies reports. Once fire season begins, all automated distribution feeders are opted
into FSM, allowing real-time adjustments to protection settings. The system now includes four levels of
operation:
1. Normal Operations (Blue)
Standard reclosing behavior—multiple attempts to restore service after a fault, prioritizing
reliability.
2. Base Level FSM (Yellow)
After a fault, the circuit waits before attempting a single reclose. If unsuccessful, it remains off
until inspected. This reduces spark energy and ignition risk while maintaining some reliability.
3. Extreme FSM (Orange)
Instantaneous trip with no reclosing. The circuit stays off until patrolled and cleared. Used only
during severe fire conditions due to its impact on customer reliability.
4. Public Safety Power Shutoff(PSPS) (Red)
Proactive de-energization of circuits in extreme fire weather (e.g., dry conditions with high
winds). PSPS is typically implemented when the Fire Risk Index reaches 7 or higher, and the
forecasted safety risk outweighs reliability concerns. Unlike FSM, PSPS disconnects power
before a fault occurs.
Key difference between Fire Safety Mode and PSPS: FSM responds to actual faults with modified
protection settings; PSPS is a preemptive shutoff based on forecasted risk.
44

Infrastructure & Automation. Avista has modernized its system to support FSM, including installing
remote-controlled reclosers and upgrading substations with automation and communications
equipment. These upgrades allow for dynamic protection adjustments and remote operation,
significantly enhancing wildfire mitigation capabilities.
Strategic Balance. FSM prioritizes public safety over system reliability. Enhanced protection settings
may lead to broader outages if a fault occurs on a line serving multiple areas. Avista uses data-driven
decision-making to balance wildfire risk with customer impact, applying FSM and PSPS judiciously.
Fire Safety Mode Begins Fire Safety Mode Ends
2025 2024 2025 2024
Jun 2 Jun 26 Oct 14 Oct 16
,Jun Jul ' • Sep Oct •
t
Jul 5 Jul 18 Oct 2 Oct 17
2023 2022 2023 2022
Year-over-year comparison to when entering and exiting Fire Safety Mode
Workforce Training and Practices
While infrastructure and vegetation investments make up the bulk of Avista's Wildfire Plan costs,
workforce training, partnerships, and customer engagement are equally vital to wildfire resiliency.
Many of these efforts are built on existing programs and relationships, and they deliver meaningful
benefits—reducing operational risk and strengthening collaboration with fire protection agencies,
emergency managers, and state partners like IDL and
Washington DNR.
Colville*
Sandpoint
Internal Training. Avista's electric line personnel, spread Coeur d'Alene
*park
across 12 districts, respond to a range of electric trouble calls, Davenport
including those involving wildfires. Prior to fire season, * * * * Kellogg
divisional managers conduct monthly safety meetings Spokane *St.Maries
featuring wildfire-specific training led by Avista's Wildfire
*Othell *PullmQ
Team, which includes staff with wildland firefighting
experience. Lewiston/
Clarkston
Training emphasizes:
• Coordination with fire authorities before inspecting or Avista Service Districts
re-energizing circuits.
• Understanding fire behavior—including the effects of terrain, weather, and wind.
45

• LCES principles:
o Lookouts assigned to monitor fire conditions.
o Communication with fire personnel is critical.
o Escape Routes planned in advance.
o Safety Zones established for crew
protection.
_ I
Crews are also trained on heat and smoke exposure ,
risks, and take precautions such as avoiding dry �:- • s-
vegetation and off-road travel during high-risk - _.,� t ---
conditions. Vehicles are equipped with pressurized -
water cans, and in higher-risk areas, crews bring 500-
gallon water trailers to job sites. Avista has partnered with firefighters throughout
our history.
External Partnerships. Avista's wildfire response is built on strong relationships with first responders,
emergency managers, community leaders, and state agencies. These partnerships enable coordinated,
proactive responses to wildfire threats.
As part of the Wildfire Plan, Avista engages in cross-training with fire protection agencies. This ensures
Avista personnel understand fire incident command structures and their roles during active events,
while fire professionals are educated on electrical hazards to stay safe near utility equipment. Though
Avista crews have basic fire safety training, they defer to professional firefighters during wildfire
events.
For further details regarding preventing and mitigating fires while performing Avista work, please refer
to Appendix E.
Operations & Response Budget & Targets
For detailed budget and target information related to Operations and Response programs, please refer
to Appendix B.
46

PUBLIC SAFETY POWER SHUTOFFS
Public Safety Power Shutoffs (PSPS) are a last-resort wildfire mitigation strategy used to proactively de-
energize power lines in areas facing extreme fire risk due to a combination of severe weather
conditions like high winds and low humidity. Unlike Fire Safety Mode, which adjusts protection settings
and only interrupts service after a fault occurs, PSPS involves preemptive shutoffs based on risk
assessments to prevent spark events before they happen.
Avista's PSPS Plan outlines the criteria, protocols, and coordination efforts involved in these events.
Decisions are informed by our Fire Weather Dashboard, which calculates a Fire Risk Index using factors
such as wind speed and direction, fuel conditions, infrastructure vulnerability, and community impact.
Coordination with emergency managers, critical facilities, and affected communities is central to our
approach, along with efforts to minimize disruption through backup systems and communication
strategies.
Each PSPS decision is made with careful consideration of real-time conditions and local context. While
PSPS is rare and disruptive, it is a critical tool to protect lives, property, and infrastructure when
wildfire risk is exceptionally high.
For full details on Avista's PSPS strategy—including operational protocols, coordination plans, and
decision criteria—please refer to Appendix F.
Avista's Purpose and Scope for Public Safety Power Shutoff Events
partnersAdvancing the safety o Working with key Minimizing wildfire risk Maintaining reliable
customers,communitiesi external
employees.and Avista
government.
Safety Collaboration Risk Reduction Reliability
Wildfire Emergency Operations Plan (EOP)
Avista's Emergency Operating Plan (EOP) outlines the command structure, roles, and procedures used
during emergency events, including wildfires. As part of our Wildfire Mitigation Plan, a specific EOP was
developed to support high fire risk scenarios and guide the implementation of Public Safety Power
Shutoffs (PSPS).
Unlike traditional storm response, which reacts to system damage, PSPS is a proactive decision to shut
off power based on elevated wildfire risk. This requires detailed planning, coordination with
emergency managers and critical facilities, and clear communication with affected communities.
47

PSPS and Transmission
Avista has expanded its PSPS strategy to include portions of the transmission system, recognizing the
added complexity and broader impact compared to distribution lines. Transmission lines are part of the
Bulk Electric System (BES), which supports the reliability of the Western grid and carries heavy summer
loads. A transmission outage can affect a large number of customers, utilities, and contractual
obligations, making PSPS decisions at this level more sensitive and situational.
For the 2025 wildfire season, Avista added steps to implement non-reclosing protection schemes on
select 115kV transmission lines if the Fire Risk Index (FRI) exceeded 5.5. Lines with remote automation
may be dynamically placed in and out of non-reclosing mode, while manual adjustments require
additional analysis and field coordination. Avista also works with neighboring utilities to manage joint
transmission line operations during elevated fire risk. There were no instances in 2025 of the FRI of a
transmission line going above 5.5.
For more details on transmission-level PSPS protocols, decision criteria, and operational procedures,
please refer to Appendix F.
Conditional De-Energization
Avista uses several types of de-energization to
reduce wildfire risk and protect public safety.
These include:
Media Alert
• Conditional De-Energization: Selective Contact:
David Vowels,[phone],[e-mail]
shutoffs of equipment or lines with no Avista 24f7 Media Access(509)495-4174
immediate customer impact, at the Avista customers in Kettle Falls to experience a planned power outage
decision of System Operations during Spokane,Wash.,July 21,2025:Approximately 330 Avista electric customers in Kettle Falls will
experience a planned power outage on Friday,July 25.The planned outage will start at 8:30 a.m.and
elevated fire risk or Storm events. end at2:30p.m Impacted customers will be notified.
During this time,Avista crews will be performing maintenance on equipment in the area.Avista is
• Planned Work: For wildfire resiliency or continually updating equipment and infrastructure to increase the safety and reliability of its system
infrastructure upgrades, customers are Customers who have questions or concerns can contact Avista at(800)227-9187
notified in advance through mailers, calls, Avista media alert for a planned outage
and other outreach. Large projects may include community meetings and media engagement.
• By Request: Avista routinely de-energizes lines at the request of first responders to protect
firefighting personnel. This applies to both distribution and transmission systems and is
coordinated through incident command structures.
• Wildfire Encroachment: Lines may be proactively de-energized if fire or smoke threatens
infrastructure, based on field reports and situational analysis.
• Third-Party Providers: Avista coordinates with independent generators and other utilities
connected to its system. If safety concerns arise, Avista may de-energize shared infrastructure,
with ongoing communication to affected parties.
48

De-energization decisions balance wildfire risk with the need to maintain service, especially for critical
infrastructure and medically vulnerable customers. Restoration after a PSPS event involves thorough
inspections, coordination with fire personnel, and may require mutual aid or aerial patrols. Access,
geography, and weather all influence restoration timelines.
Customer Support
Avista is committed to helping customers prepare for and navigate Public Safety Power Shutoff(PSPS)
events, recognizing the potential hardships and safety concerns caused by extended outages. These
events are only implemented after careful evaluation, and we work to minimize disruption through
proactive communication, support centers near impacted areas called Community Resource Centers,
and a Battery Backup Program for customers who depend on medical devices which need 24/7
electricity.
We prioritize coordination with public safety partners, municipalities,Tribal authorities, and critical
service providers such as hospitals, airports, and communications systems. Our CARES team supports
customers with special needs, and we provide outage maps, educational outreach, and real-time
updates through multiple channels.
PSPS decisions are made with sensitivity to customer impact, balancing wildfire risk with reliability.
Restoration efforts are carefully planned and may involve mutual aid, aerial patrols, and prioritization
of essential services.
Community Resource Centers
In the event of a PSPS,14 Avista may stand up Community Resource Centers (CRCs) in areas impacted
by a PSPS, to be managed by Avista and staffed by Avista Community Response Ambassadors, who are
individuals volunteering to help our customers in emergency situations. The services offered at a CRC
include electronic and/or medical device charging, internet access, water, light snacks, and updated
real-time information to offset some of the impacts associated with a PSPS event. The CRCs are
carefully chosen to be accessible to areas most likely to experience a PSPS.
As we continue to refine the CRC program, fine-tuning locations, resources needed, and Avista staff
training. As of year-end, 2025, seventeen CRC's have been identified.
In 2025, the CRC program actively installed to date its first manual transfer switch (MTS), which allows
switching portions of the designated CRC location within the building over to a generator if the power
is out, allowing the center and community to become more resilient. The team plans to have an MTS
installed at every CRC location that currently has no back-up generation by the end of 2026.
In 2026, Avista will continue its outreach and education efforts by collaborating with multiple
partnering agencies highlighting both the importance of PSPS and the available resources the CRC
program provides for the communities we serve.
49

Battery Backup Program
With the implementation of PSPS, customers with medical
equipment that sustains life could be significantly impacted when
the power is out. A PSPS event can be lengthy due to the
requirement to fully patrol the impacted line before putting it back
into service to ensure that it is safe to re-energize. We developed
the Battery Backup Program to provide medically qualified
customers who depend on medical devices which require 24/7
electricity with a battery backup system for use during power
outages. We engaged with partners including Aging and Long-Term portable power bank
Care of Eastern Washington, who helped us develop this program and battery
determine what type and what size battery would be needed in order to
support customer medical devices for multiple hours. Postcards regarding this program were sent out
starting in early June 2024 to registered life support customers in the highest wildfire threat areas of
our service territory. In 2024, Avista delivered around 71 batteries. In 2025 we sent out additional
postcards and Avista delivered 136 batteries. Avista's
Customer Assistance Referral and Evaluation Services (CARES)
Team collaborates with medical providers to verify customers
having significant dependency on electricity for medical
devices and their eligibility for the program.
Participant Qualifications. This Program is available to
customers who have been verified by a licensed physician as j
medically dependent on electric life support equipment. GDAL
Customers are required to fill out an application and have their Goal Zero Yeti Pro 4000 portable
primary care physician validate their medical need. powerstation
Recertification is needed bi-annually for the account to remain in the CARES life support caseload. In
most instances, eligibility means that a customer is dependent on their medical device 24-hours a day.
However, medical devices like dialysis machines (not used 24 hours a day) also qualify for the program.
Other qualified medical devices include oxygen respirators, ventilators, iron lungs, feeding or infusion
pumps, and ventricular assist devices. Customers who have a backup home generation system and/or a
battery backup are not eligible for an Avista-provided battery. The customer must agree to and
acknowledge the backup battery terms and conditions.
50

Program Goal. The goal of the program is to
provide medically vulnerable customers with a
portable battery to give them additional time to
make decisions in the event of a PSPS event. The
threat of power disruption for those who are Dear Jenny,
dependent on electricity for their medical Wildfire season is here,and we want to remind you that the nsk of power outages may increase,
which can impact medical equipment that relies on continuous electricity.Your safety and well-
equipment may make it challenging for them to being are our top priorities.
make informed and rapid decisions. Therefore, To support our customers who depend on 24-hour electricity for medical devices,Avista is
offering a complimentary 4000x Biol-ite battery specifically designed for medical equipment.
having a battery capable of giving them 6-8 If you feel that your household may benefit from this support,please call us at(888)700-
hours or more of additional time if the 2757,Mond ay through Friday,between 8a.m.and 5p.m.If you qualify,your battery will be
( ) p ower shipped to your residence at no cost.
goes out allows them the flexibility to We also encourage all customers to have an outage preparedness plan in place.For additional
information and resources,please read aboutAvista's Life Support program at
implement their emergency plan and make myavista.comlmedicalequipment.
arrangements when necessary- Additionally,as part of our ongoing commitment to safety,we have enhanced our measures
to help prevent wildfires.This includes setting line breakers to be more sensitive and,in some
cases,proactively shutting off power in certain areas during extreme weather conditions.Visit
myavista.comlwildfire to learn more.
Program Cost and Specifications. Customers
are not charged for these batteries. The initial Sincerely,
The Avista Customer Care Team
cost per participant for the battery in 2025 was
approximately$3,000. This included a portable Avista customer contact offering a backup battery
Yeti 4000x battery, which provides over 3,600
watt hours of electricity use, the processing fees from the battery distributor, and shipping to the
primary residence of the customer. In 2025 136 customers were gifted batteries. It is expected that this
program will have less participation in 2026 due to the saturation rate of qualifying customers.
PSPS Coordina tion
Avista has a structured communication plan to support coordination throughout the lifecycle of a
Public Safety Power Shutoff(PSPS) event. Before fire season, we focus on education and preparedness
with emergency managers, public safety agencies, and community partners. During fire season, we
actively engage with these stakeholders and the public to ensure timely updates and coordinated
response. After the season, we evaluate outcomes and identify areas for improvement.
When a PSPS is planned or initiated, Avista works closely with impacted parties, especially those
responsible for public safety and critical infrastructure, to ensure clear communication and minimize
disruption.
Other Utilities
Avista is working closely with our neighboring utilities on wildfire issues, including PSPS. They are
invited to participate in our tabletop PSPS exercises and engage in our annual Partner Forum. We share
our technologies with them, specifically our Dashboard, wildfire camera feeds, and weather station
data. We are currently working with our directly interconnected neighbors to produce a list of shared
substations and transmission lines that may cause impact, including sharing maps to allow
51

coordination during a PSPS. These maps will allow us to quickly identify areas of impact and what
infrastructure of each may be affected. We are working together to provide area fire departments with
these maps so they know which facilities belong to each utility to make contact and communications
more streamlined.
Most co-ops and public utilities in our area do not have a formal PSPS plan, so we are sharing our PSPS
processes with them to help them get started. We work with them, as well as the Washington DNR and
the IDL, to locate our camera and weather stations so we coordinate and complement rather than
overlapping these resources. We are committed to helping everyone be safe and thus share resources
when possible.14 We are also working together to identify shared sites for Community Resource
Centers. More opportunities to partner with other utilities on this issue will likely come up as they
move forward with their own plans.
Emergency Management Agencies
Emergency management agencies are considered key partners in Avista's wildfire efforts and are
engaged in a spectrum of efforts related to this work. They join in our annual Partner Forum in which
participants receive updates on wildfire mitigation strategies and work together on strategies. They are
invited to join in cross-jurisdictional collaboration (which includes other agencies and Tribal nations)
and take part in scenario-based discussions to refine communication protocols. They are also invited to
be active participants in our annual Telephone Town Hall discussions appropriate to their jurisdictions.
They have helped provide training to our employees in supporting customers during PSPS events (the
Red Cross trains our CARES team) and provided input to our wildfire strategies. They provide customer
support during outage events.
Avista's Regional Business Managers (RBMs) play a central role in our external wildfire-related
outreach and engagement efforts. They are responsible for direct communication with emergency
management, public safety partners, local governments, and critical infrastructure operators such as
water and wastewater utilities. Their work ensures timely, accurate, and appropriate communication
with all impacted parties before, during, and after wildfire season, including any Public Safety Power
Shutoff (PSPS) events. Prior to wildfire season, these employees conduct education and outreach on
Avista's Wildfire Plan, including mitigation strategies, communications, how we will engage with them,
key mitigation activities, and public readiness initiatives.
In the event of a PSPS, the associated RBM provides advance notifications via phone and email to
impacted partners including emergency management, public safety, local government, and critical
infrastructure operators, and will provide real-time updates to these customers. They help ensure
continuity of essential services. After an event, they provide restoration information and updates.
14 Sharing of some of our technologies is limited by contractual agreements.
52

Critical Service Providers
Prior to an event, Avista Account Executives review the PSPS impacted feeder lists as soon as they are
provided by Operations, identifying any commercial and industrial customers or critical service
providers on the impacted feeder(s). They reach out to these customers directly. The Account
Executives work with these customers before an event for notification, during the event to provide
updates, and after an event to ensure that the customer is back in operation. These customers are
provided advanced notice via phone and email as well as real-time updates and post-event restoration
timelines with the goal of ensuring continuity of essential services.
Communities 0 0 0 0 4W 1W
When a PSPS event becomes likely, the
Avista's Wildfire Team will reach out to
the community partner who has agreed to lirlirn
SMS Text, Social Website Town Hall Pre-Season Special
host a Community Resource Center in the Email, Media Meetings& Educational Outreach to
Phone Events Outreach Vulnerable
area of the anticipated PSPS. The host will Customers
be given as much notice as possible to ensure that the
center is ready and available for use. The Company's External Communications team issues a message
to impacted customers about the potential for a PSPS along with information about the CRC location,
hours, and provisions. Avista Community Response Ambassadors will be dispatched to the CRC to
provide customer information and support.
Tribes
Avista's American Indian Relations team meets with our regional Tribes at least annually providing
information about Avista's Wildfire Plan for the upcoming fire season. Our wildfire-related plans and
strategies are shared with the Tribe's leaders as well as their emergency management, natural
resources and social services departments. The annual update includes wildfire prevention measures
such as tree maintenance, access to camera and weather station data, situational awareness, and how
Tribal authorities can partner with Avista in wildfire preventative measures on the reservations. Tribal
communication includes general education about Avista's wildfire efforts and Public Safety Power
Shutoff pre- and post-event engagement. Avista also works with the Tribes to identify customers with
medically vulnerable life support needs as well as securing locations for Avista to host community
resource center(s) in case of a PSPS event within Tribal jurisdictions.
53

Commissions
Our state utilities commissions have the expectation
of being notified when we enter Fire Safety Mode 0000 Avista Commission
and if we implement a PSPS event within their Communication
respective jurisdictions. As a course of business, we
Sept. 29, 2024, 1:20 PM Update—the Company
send them information about our curtailment has decided to call a PSPS for the approx. 1500
process, the notification process, the alert, who is customers served off of Indian Trail 12F2.The
being impacted and contacted, and large customers de-energization will occur around 1:45 PM in
that may be impacted. This information includes a advance of peak wind conditions starting
situational report containing start date and time, around 2PM.We expect the weather pattern to
pass later this evening, and when it is safe we
location, duration, customer count, cause, contact, will patrol the line and safely reenergize.We
and time and date of restoration.15 In Idaho and have a Customer Resource Center set up at
Washington, this includes direct communication with Mead High School.There are no known life
the ESF-12 Coordinator. support customers,and only one part-time
medically vulnerable customer that we will
reach out to specifically(beyond the
PSPS-Specific Communications communications and out-bound phone calls
already made to affected customers).
Effective communication is central to Avista's Public Communications are being made right now to
Safety Power Shutoff(PSPS) strategy. We engage impacted customers that a PSPS is
with customers, emergency managers, public safety imminent.We will provide a further update
agencies, Tribal authorities, and community later this afternoon (or sooner if warranted).
organizations before, during, and after fire season to
Example of Avista's outreach to
ensure awareness, preparedness, and coordinated response. the Commissions during a PSPS
Before Fire Season. Avista hosts virtual town halls, distributes educational materials, and conducts
outreach to special needs and life-support customers. We also hold an annual PSPS Partner Forum to
align with external agencies and refine cross-jurisdictional coordination.
When a PSPS is under consideration, we notify customers and partners through multiple channels:
email, IVR calls, text alerts, social media, website banners, and outage map updates. We also connect
customers to additional support services, including 211 and local aid organizations.
95 For the Washington Commission we contact electric-outage(nb.utc.wa.gov and for Idaho we contact secretary a(,.puc.idaho.gov,
0utage.Alert [e-mail].
54

During a PSPS Event. Avista provides frequent updates on outage duration and restoration timelines.
Our CARES Team supports medically vulnerable customers, and Community Resource Centers (CRCs)
offer device charging, internet access, clean water, and real-time information. CRCs are staffed by
trained Avista employees and Community Response Ambassadors.
7)<t> /,AF X9
PSPS Watch PSPS Warning PSPS Imminent PSPS Outage Alert PSPS Updates PSPS Over
Sent when Sent when Sent when Sent when Sent as needed and Sent when
a PSPS event a PSPS event a PSPS event a PSPS when restoration power has
is possible. is likely. is imminent. outage begins. work begins. been restored.
After Fire Season. Avista conducts after-action reviews with internal teams and external partners to
identify lessons learned and improve future PSPS operations.
For full details on Avista's PSPS communication protocols, notification procedures, and coordination
strategies, please refer to Appendix F.
Vulnerable Customer Outreach
In 2022 we began an effort to better ,
f Ave.#of Medical Equipment
identify and support our most vulnerable Life Idaho Life Enrolitments
customers. Many of our communities are SupportWashington " Jan 2
Accounts Accounts Feb 0
rural or represent limited-income 2020 158 Mar 0
populations. Avista's Wildfire PSPS 2021 179 2021 179 Apr 5
May 103
program leverages data collected on 2022 171 2022 171 Jun 437
vulnerable communities to help overcome 2023 150 2023 150 Jul 75
202
customer barriers and enable us to utilize 220 20 220 Aug 9
2025 261 2025 2 Sep 2
261 92
a multilingual and multichannel Oct 53
Avista life support and medical equipment Nov 38
communication strategy to reach these customer counts are increasing due to our oPc 25
communities. In addition, medically outreach efforts
Jan 21
vulnerable customers could be Feb 36
significantly impacted when a PSPS is implemented. This puts customers dependent Mar 42
Apr 48
upon medical devices at risk. We use our communications channels to ask May 64
customers to report themselves or family members if they need specialized Jun 126
Total 1,239
assistance and have developed the strategies mentioned earlier to provide support.
We have developed several ways of reaching and supporting our most vulnerable customers.
55

2025 PSPS Activity
Avista did not implement any Public Safety Power Shutoff(PSPS) events during the 2025 wildfire
season. While conditions warranted close monitoring, no situations met the threshold for proactive de-
energization. We continue to learn from each season through system observation, stakeholder
engagement, and internal reviews, refining our processes and readiness for future events.
For more details on PSPS protocols, planning, and decision criteria, please refer to Appendix F.
56

PREPARING FOR WILDFIRE SEASON
Preparing and Training Employees and External Partners for Wildfire Events
Since 2019, Avista has been building relationships and partnering with local emergency managers, first
responders, fire districts and elected officials across our Washington and Idaho service territory in
support of Avista's Wildfire Mitigation Plan. This includes county and city emergency managers, local
emergency planning committees, local public health jurisdictions, fire chiefs, critical infrastructure
providers, public safety leaders, and a variety of elected officials. Interactions with these key public
safety partners include attending meetings to present and discuss the Wildfire Mitigation Plan
(including PSPS, working with municipalities and agencies to identify critical infrastructure, updating
the notification process (who, how and when) for PSPS, working with some of these partners to
identify locations for Community Resource Centers (CRCs) in the event of a PSPS, and working with
support agencies to identify vulnerable customers. Many of these partners were instrumental in
developing the Plan, helping us create strategies (such as Expedited Response) and implementation of
Plan elements. We also invite these partners to participate in tabletop exercises and other
engagements such as cross-training opportunities to continue to build readiness, awareness, and
relationships around PSPS. They also participate as guest experts in Avista's series of annual Wildfire
Telephone Town Hall meetings.
Customers Emergency Mgmt.
Safe Tree,PSPS Education& PSPS Prep&Response,
Preparation I Vulnerable Customers,
Outreach&Support
IDL/DNR / Avista . .-
=74P Cameras,Expedited
Response,Fuel Reduction, Wildfire
EOP
External
E
Partnerships
57

Partner Forum
As mentioned above, each year we bring our public safety partners together to learn more about our
ongoing preparations for the upcoming fire season, any changes or updates we have made or are
planning to make to our Plan or strategies, and to help begin preparations for a PSPS event. The
Partner Forum brings together a wide array of participants, including first responders and emergency
responders who serve both Avista service territory and adjacent utility service areas, land management
agencies for both Avista's service territory and contiguous jurisdictions, and Tribal governments and
Tribal emergency response personnel. This forum, which has been held in prior years as an annual
Tabletop Exercise, evolved to share updates on our wildfire mitigation strategies and Wildfire
Mitigation Plan and encourages participant cross-jurisdictional teamwork and communication. During
the time together, Avista leads scenario-based discussions to test and refine communication protocols
and strengthen alignment across agencies and Tribal nations for emergency response. The goal is to
help ensure that all partners are informed, aligned, and prepared for the upcoming wildfire season. In
addition, it is a place where we can share what we have learned and our tools, especially with the
smaller utilities who may not have the resources available to Avista.
Tabletop Exercises
Tabletop exercises help prepare Avista's internal response teams and provide an opportunity to
practice the activities performed during an actual PSPS event. During the tabletop exercises, a realistic
scenario is set up, and incident management teams go
through the scenario as if it were occurring, developing
strategies including customer outreach, crew placement, s r
damage assessment, mutual assistance requests, and
planned restoration efforts from the beginning of the
scenario event until final restoration and return to normal
operations. Participation of state and local agencies allows
the teams to practice coordination efforts. Participants
have noted that it enhanced their knowledge of 1
emergency response plans, procedures, and strategies,
allowing them to improve their performance. It also
helped identify opportunities to improve capabilities to
respond to real events. Including Avista's community Tabletop exercise
partners has been incredibly valuable and appreciated.
These external parties tell us that they leave the exercise session with a better understanding of how
we respond to events, which helps to level-set expectations during actual severe events. The
relationships forged and having both sides learn each other's "language" helps Avista more easily
integrate into Fire Incident Command to provide adequate support and information to fire teams
during an incident. This joint practice helps all sides understand each other's roles and responsibilities.
58

Partner Portal 3 4
Avista saw the need to
of
employ a more strategic Customer Custom
ap of ers
Impacts Custoand coordinated 1C
approach to reducing Map of
Areas s
wildfire risks by more Progression
efficiently notifying our '
safety partners using an lk
automated, digital systemODJ,related to Public Safety `
Power Shutoff events.
These partners include both internal and � 8
external staff, but the Portal J
is not available to regular Avista Partner Portal services
customers. It is focused on
agency partners and requires a non-disclosure agreement for use. The Portal is designed to support
Avista, its customers and our public safety partners from the start of a potential Watch/Warning/PSPS
to the final stage of re-energization. This notification system will help reduce the time it takes to
manually notify partners for a PSPS event and increase the percentage of partners receiving
notifications within a specific, often very limited, timeframe.The portal will inform critical service
providers, business partners, and customer care providers about the latest events, locations, and
affected parties. It will be a springboard for additional tools they can use, including maps, feeder and
customer data, and locations where customers may need additional assistance. It will also provide real-
time access to Avista's weather station and wildfire camera feeds. This system will provide:
• Alert Notifications: Provide notification on potential PSPS, as well as patrolling and restoration
efforts.
• Tracking of Events in Real Time: This includes maps and accurate, timely, actionable information
our partners can use to support customers across our service territory.
59

• View of Weather
Stations and Wildfire
Cameras: to provide
real-time awareness
of conditions that may
impact the customers ' Feeder
GIS D. . D. a/Critical
in their jurisdictions. Downloads Resource
• One Stop Shop for PSPS i Critical Facilities Polygons to show
Outage Information: Securely download Identification of feeder information Additional links to
GIS data within the facilities critical to and C RC locations- social media
Continually updated, Avista service public safety— view of wildfire platforms,MyAvista E
streamlined, territory using data additional support cameras and page,and additional
consistent data and share. for customers. weather stations. information.
messages to keep them Avista PSPS Partner Portal resources&provisions
informed.
• Secure Access: The portal provides life support customer lists and a list and map of critical
facilities in the area of the outage. This data is protected by double authentication to protect
customer privacy.
• Shareable and Searchable Historical Data: to add with data requests.
The Portal is currently being developed and is anticipated to be in place prior to the 2026 wildfire
season.
Firefighters
Avista has good relationships with the firefighting agencies within our service territory. These experts
were helpful in formulating Avista's initial Wildfire Resiliency Plan (now known as Wildfire Mitigation
Plan) and have continued to be crucial partners in the effort to reduce and mitigate wildfire risk. These
partnerships have been created in part due to Avista's willingness to quickly respond to situations at
the request of fire officials, such as opening fuses to shutoff power and protect the firefighters
responding to a house fire or de-energizing transmission lines in order to protect firefighters
responding to fires near the lines.
Avista consistently works with fire officials in Washington and Idaho to share information about our
operations and what we are doing to decrease spark events from our equipment. We also solicit
information about agency priorities and high-risk areas to better coordinate our fire mitigation
activities with these experts. Avista is recognized as a partner with the major fire agencies and is
invited to participate with them in pre-fire season planning meetings and post-fire season reviews as
well as coordination during fire events and participation in their Incident Command Structures.
60

Avista is also an active participant in the Inland Empire
Fire Chiefs Association. We were asked to join in their
meetings to add input on critical infrastructure
capabilities and needs during wildfire and other
emergency responses, and our shared interests have
kept us involved. This group includes the Fire Chief of the
City of Spokane and the Chiefs of Spokane County as well ,tom
as the Spokane County Department of Emergency Strategizing with firefighters
Management and the Spokane County Sheriff's
Department. Along with information sharing, this relationship has brought a heightened awareness of
how fire and emergency response is coordinated and how the utility can integrate into emergency
response efforts.
Large wildfire situations trigger a Fire Incident Command Structure (ICS). The ICS is a standardized
approach to the command, control, and coordination of the fire response from beginning to end,
allowing the various agencies responding to the fire to work together efficiently. It provides
components such as common terminology, integrated communications, and a unified command
structure over all the jurisdictions and personnel involved. Avista's strong relationships with fire
professionals, strengthened by our work with them on the Plan, have brought them into our internal
discussions and Emergency Operating Plan (EOP) processes and ensured that Avista is successfully
engaged and integrated with them in any ICS situation. This teamwork approach helps our personnel
understand what is expected of them and how they can assist and support fire command, from
selectively de-energizing lines to protect firefighters to helping ICS understand where our
infrastructure is located and potential impacts.
Key Safety Partners
As mentioned earlier, Avista hosts annual tabletop exercises with first responders each year, providing
realistic situations that allow participants to experience and react to wildfire simulation events and
practice response and joint engagement. We include external partners such as the Washington DNR,
IDL, and the Red Cross as well as adjoining utilities. The exercises are designed to simulate an actual
wildfire situation with a realistic scenario that the participants must react to. They go through this
simulation as if it were occurring, including developing strategies around customer outreach, crew
placement, damage assessment, mutual assistance requests, customer communications and support,
and planned restoration efforts from the beginning of the scenario event until final restoration and
return to normal operations. The teams then go through an after-action review to identify areas of
strength and opportunities for improvement. These joint exercises strengthen our relationships and
help us understand each other's roles in a wildfire event as we assess EOP practices, procedures, and
communications against a simulated fire situation. Practice sessions allow participants to improve their
performance and identify opportunities to advance capabilities in responding to actual events.
61

We have also been in
QEacer 4EATyE �Olut,
communication with (0,v� �"' ' 9 ° �D�
Washington State's Energy Q��. o °io ,,°�
E
�F ge
Resilience and Emergency gTyoF i w,l.iTc
Management Office, T -IF
0
participating with them in their m DAII
99I
-110 Al2A#H 7nconn roWER
_,--r- Jt'SMINGIOh
April 2024 PSPS workshop and WASHINGTON STATE DEPT OF
PUGL nATURAL
inviting them to participate in �SNERC ;, RESOURCES �.
0�t
ENERGY' �, .. ." nsTrlbe
our PSPS exercises. The two 1 °`NATd� wI°deans
'SHIN070
teams have developed joint �' J TIff IN CALIFORNIA
EUDISON'
communications protocols and
NorthWeE erri
r' "yj «tea
processes around a PSPS event °RNAiUa►�
F.ner�v
and believe we have a strong 'T,
partnership in place.
Some of Avista's partners
Interactions with these key public safety partners also include attending meetings to present and
discuss each year's Wildfire Mitigation Plan (featuring PSPS), working with municipalities and agencies
to identify critical infrastructure, updating the notification process (who, how and when) for Extreme
FSM and PSPS, and working with some of these partners to identify locations for Community Resource
Centers (CRCs) in the event of a PSPS.
With the addition of Public Safety Power Shutoffs (PSPS) to our plan in 2024, Avista reached out to all
of these partners to communicate the changes. Avista responds to many requests for presentations
from a variety of government and community groups. The Community Outreach Team conducts
meetings with emergency managers across the service territory each year in addition to telephone
town hall meetings with emergency management personnel, local leaders, and customers to update
them on Avista's Wildfire Mitigation Plans.
Critica/Service ProvidersJa = f
Schools are Centers
Emergency Services Basic Services
Avista's Regional Business Managers
and Account Executives identify and ; ;
ccess forble
engage with critical infrastructure and AResp ndersstX L J 0
popuetloons
service providers in their areas (such 119pr sall.
^ (<< >>
as water, wastewater/sewer and L all
Transportation Communications
healthcare facilities). Avista also
identified commercial and industrial Public 4 J L»> -,,,,�
Safety .-Vlwa
customers for notification during PSPS WaterB Sewer
Support Agencies
events Recognizing who these B External Partners Cooling Centers
customers are, the critical services they Some of Avista's critical service providers
provide to customers and to society, and
62

where they are located makes it possible to do as much as we can to protect their energy supply
and/or restore their service as quickly as safely practicable.
Other Utilities & Industry
Starting in 2019, Avista began organizing and hosting the Pacific Northwest Wildfire Working Group
meetings. This group shares information on planning, mitigation strategies, and logistical constraints
on a regular basis. Attendees in this meeting typically include Idaho Power, Portland General Electric,
Puget Sound Energy, Northwestern Energy, PacifiCorp, and Chelan County Public Utility District, the
Washington State Energy Resilience and Emergency Management Office, and others. These meetings
have been helpful for all participants in understanding the components of neighboring utilities wildfire
plans and the challenges that implementing them has brought. These engagements help us learn about
and share best practices in our industry.
Avista is also involved with the Western Energy Institute and other national utility-based organizations
to gain learning and information-sharing related to emerging issues pertinent to utilities. The risk that
wildfire poses to utilities throughout the West is a central topic. Along with regular attendance, Avista
has shared what we are doing in response to the wildfire threat, including presenting our Plan to this
group in a formal setting, and has gained a better understanding of what other utilities are doing to
address the same issues.This is another forum in which we can share and gain best practices.
Neighbors
We have reached out to neighboring counties in Washington and Idaho (each with their own
emergency notification systems) to explore the potential for a similar partnership to help amplify
Avista's PSPS communication plan and to collaborate with them to enhance community safety. At our
annual Partner Forum we facilitate cross-jurisdictional collaboration and communication, conduct
scenario-based discussions to test and refine communication protocols, and strengthen alignment
across agencies, neighboring utilities, and Tribal nations for emergency response.
We also work with our neighboring utilities in sharing best practices, assisting with their wildfire plans
and strategies,joint preparation for wildfire events (EOP participation), PSPS related communications
and cooperative engagement, and during actual PSPS events. We share our camera and weather
station feeds and our technology when possible. Our Town Hall events also include customers outside
of our jurisdiction.
Coordination with Other Wildland Fire Protection or Mitigation Plans.
Avista's Wildfire Mitigation Plan is customized to our system and our customer base, though we have
freely shared our Plan and our methodologies with other utilities (as well as our camera feeds, WUI
map technology, Fire Weather Dashboard, and modeling). Each utility's plan is specific to them, their
budgets, their manpower, their service territory, and their own goals and objectives. We integrate the
63

U.S. Forest Service models and datasets into our analyses as mentioned earlier, and we collaborate
with them and others to support their wildland fire protection efforts in our service territory (such as
our Fuel Reduction Partnerships). We coordinate with these agencies in their work, which is based
upon their mitigation plans and strategies. Thus far we have not incorporated their wildfire plans into
our own, but we are open to improvements as we learn of them. We further note that utility
requirements, practices, and strategies may differ from those of the general industry, such as state
forestry, due to the amount of regulation under which the utility must function as well as the focus on
reliability and customer base.
Avista collaborates with many diverse external parties in planning and executing our Wildfire Plan.
These partnerships began in 2019 with the initial development of the Plan as we called upon outside
experts to help us develop our wildfire risk reduction strategies, and we have continued to grow these
partnerships and add to them over time. Some of these parties gain direct monetary benefits, such as
the Safe Tree Program that replaces risk trees on customer private property at no cost to our
customers or our work on fuel reduction with Bonner County's BonFire Program. Others have no cost
associated with them but provide direct benefit, such as the Washington Dept. of Natural Resources
calling upon Avista's Fire Weather Dashboard to help them strategically place firefighting resources
across the state based upon the Dashboard's analysis of risk. Some partners join with us in fire risk
reduction activities such as the Expedited Response contracts, others help prepare and support our
customers and communities such as public health and safety agencies.
Opera tiona/Exercises
Avista is committed to ensuring that we take the necessary steps to mitigate the risks associated with
wildfires. In addition to our Wildfire Mitigation Plan, we take seriously the need to create awareness in
our communities and within our Company of our plans and processes for managing a PSPS. Internally,
these exercises help to reinforce how we will respond to a PSPS, ensuring that employees understand
their roles and responsibilities and that as an organization, we are able to respond quickly, safely, and
efficiently, minimizing the impacts to our communities and our customers.
64

From 2023 to 2025, Avista conducted annual wildfire preparedness
exercises to strengthen emergency coordination and test its 2024 Tabletop
Emergency Operating Procedures (EOP) and Public Safety Power Exercise External
Shutoff (PSPS) protocols. These exercises involved internal teams and Partner Participants
external partners, including state agencies and emergency American Red Cross
• Clearwater Power
responders. Key outcomes included improved interagency Coeur d'Alene Tribe
• Colville Tribe
collaboration, successful integration into the Incident Command Idaho County Light&Power
• Idaho Dept.of Lands
Structure during the 2023 Gray Fire, and enhanced communication Idaho Military Division
• Idaho Public Utilities Commission
strategies. Each year's scenario built on lessons learned, refining • Inland Empire Chiefs
Avista's wildfire response capabilities and ensuring readiness to • Inland Power
• Kootenai Electric Co-Op
protect communities and restore power safely and efficiently during Kootenai Health
• Lincoln County Emergency Mgmt.
wildfire events. • Modern Electric
• National Weather Service
• Nez Perce Tribe
• Northern Lights Power
Further Insight into the 2025 Exercise. In 2025 Avista put together Pend Oreille PUD
• City of Pullman
another realistic PSPS exercise for both internal and external partners. Spokane Dept.of Emergency Mgmt.
Spokane Fire Dept.&Dist.1,3,4,9
Although the parties knew the approximate day of the event (so Spokane Regional Health District
the would be at their osts , the were not iven an details until the Washington Emergency Resiliency
y p ) y g y • Washington Dept.of Natural Resources
event occurred. The two primary objectives for the 2025 exercise Whitman County
were to address mutual assistance requirements and to review the
conditions, metrics, processes, and responsibilities for safely ending the PSPS. Avista's Wildfire
Resilience team, Electric Operations, Corporate Communications, Customer Service, Account
Executives, Regional Business Managers, Social Impact, System Operations, Distribution Operations,
Legal and other support areas from across the company participated.
The 2025 exercise identified a total of 16 feeders/circuits that would be de-energized due to fire
weather conditions combined with a weather event. Teams participated in real-time assessment
discussions and executed their activation procedures, simulating communications, notifications, and
other actions, as if they were real. They practiced communication and notification processes including
media releases, notifications to emergency and community partners and customers. They also readied
the resources and logistics to establish a Community Resource Center to provide support to impacted
customers.
From an Operations perspective, the teams demonstrated the process for assessing the impacts and
outages, determining resource requirements, and taking steps to secure additional resources to
support restoration efforts. Once the wildfire conditions and the weather event had subsided and our
PSPS thresholds began to dissipate, participants reviewed the roles and responsibilities for the decision
making that would enable us to begin to re-energize, restore and return our system to pre-event
conditions. After the exercise members met to discuss what worked well and identify areas of
improvement.
65

GENERAL WILDFIRE PUBLIC OUTREACH AND ENGAGEMENT
Beyond our PSPS communications, a key element of our Wildfire Mitigation Plan is ensuring that all
interested persons know that the plan is in place and that Avista is taking certain precautionary steps
to reduce wildfire risk. A strong and effective strategic communications campaign is important in
ensuring broad awareness and in demonstrating Avista's commitment to reducing the impact of
wildfires. Avista's Wildfire communications plan is directed at Avista's key participants including
customers, employees, state and local government officials and regulators, law enforcement and fire
departments, local media, and shareholders. Our wildfire communications goals are to create
awareness of Avista's work to reduce the risk of wildfires, promote the safety and well-being of our
customers, and to engage customers in programs that impact them and their communities.
Below we discuss our general wildfire communication efforts and outreach. More of our
communications strategy can be found in Appendix F.
Avista Wildfire Communications
Avista's communication strategy is designed to build ;
awareness of our wildfire mitigation efforts, foster trust, '
and promote customer preparedness. Key objectives __�®r
include highlighting system investments, demonstrating
our commitment to safety, and engaging customers in
programs that impact their communities. Wildif ire season
We tailor communications to each initiative, such as is here.
vegetation management, grid hardening, Fire Safety Mode, Avista is ready.
and PSPS, using a mix of channels: email, IVR calls, press
releases social media outage map updates and direct Dryvires.B tAinstn and hghiNo increase the chances of
� � � wildfires.But Miztn a doing our part to keep cur system
and comntury ties safe.
outreach. Customers are notified of nearby projects and We are partnering mth oroperTy owners to remove a trim
trees near our Imes-We are making improvements to nuke
potential outages through postcards, letters, phone calls, our system sttonger.And—arc charging operation when
hot."ndy forecasts are predicted In area of higher risk.vve
and local ads. For larger efforts, we host community can set the system to to more sensitive.near rig we dcn't try
and reenergize automatically if something comes in contact
meetings and town halls. withahne-We physically patrol the lirse when it's safe to
rruke sure there is na fire danger before reenergimnig.
Our system is bu It to keep outages to a minimum but help
us keen you informed.log in and update your contact
Outreach includes: .mforrrotior on our website.Also sign up to recene
ooweroutage alerts by test or mobile app.
ak*the ward-outage-it the top uivigatsori to
• Avista Connections newsletter articles and seasonal b—te the ooge.We.jst want to keep you safe.
_earn more about our wildfire measures at
updates. myaresta.corsvNviklfire
• Customer emails with wildfire safety tips and service
alerts.
66

• PSPS notifications via aMISTA
email, IVR callout and
Your Account Save Energy Safety Outages About Us Contact Us
media. At
• Telephone town halls
with local leaders and
emergency personnel.
• Print ads in rural
communitiesWe'redoing mor_ to : ,ainstwildfires
encouraging contact AL
updates. A wise investment in preparedness
Call 811 Be/ore You Dig in Washington,Itlaho,or
• Community meetings Avista is committed to keeping people and property safe.So,we are expanding our current safeguards for Oregon
preventing,mitigating and reducing the impact of wildfires with a new enh—ed 16year Wildfire Resiliency
led by regional Plan. Safety Around Dams
managers in high-risk me%uning
areas.
Wildfire Community Engagement Team
In 2022, Avista created a subcommittee known as the Wildfire Safety & Community Engagement Team
to develop an outreach framework. This team still exists today and continues to improve on the three
key focus areas that they were provided in the beginning:
1. Develop a long-term outreach plan to educate communities about Avista's Wildfire Mitigation
Plan, procedures, and Fire Safety Mode operations. PSPS outreach was added to the list in 2024.
2. Gather insights from communities on how we may better engage with them in the short-, mid-
and long-term rollout of the Plan's deliverables.
3. Select a subset of community members to help Avista set the course to better inform and identify
opportunities for future outreach and partnerships in public safety and engagement.
This team is composed of leaders that are responsible for the
y
delivery of the existing Wildfire Mitigation Plan 7owkihalls for All Po I� ti
nes Energia
Cus+omers (Teaerald, . VOS de
Specific uridad Publiea
through their support of our customers �m�uhity ;
LeaAcrsd Firs+ Ou+reach da
and the communities we serve. This ResponAers
includes Regional Business Managers as
well as employee representation from
Operations, Customer Solutions, Legal, yAultipleChannels 4+ ,1 �
Communications, Community Outreach, _.
Social Impact,Tribal Relations, and _ 's
Engineering.
67

This Team is committed to
reinforcing key messages of the
Wildfire Plan and reminding dO ,,
customers of the actions and
Northeast NC Idaho/ 5 kane ion North Idaho Palouse
investments Avista is making i Washington LC valley P° '�
to reduce the risk of wildfires. Stevens County Clearwater County Greater Kootenai County
• Ferry County •Asotin County Spokane Valley Benewah County
•Lincoln County •Lewis County •Liberty Lake Bonner County
They promote wildfire Spokane County •Lewis&Clark Otis Orchards Shoshone County
Nez Perce
readiness along with key Whitman County
partners.
Regional Business Manager territories
Another Team goal is creating a
list of key contacts within each WUI Tier 2 or 3 community, often community leaders or other
individuals who will be educated about the Fire Safety Mode practices to help communicate with their
communities in response to emergency situations related to Avista. They also built a strategy around
expanded outreach to life-support customers during unplanned outages and standardizing the Town
Hall outreach efforts to communicate more consistently. Another benefit of this Team is helping the
Company determine the language needs in our communities in order to create multilingual options in
our customer outreach materials.
In 2024 this team developed a consistent script to use for the Telephone Town Hall meetings. The
Regional Business Managers send this script to area speakers (often non-Avista) that will be addressing
Fire Safety Mode and PSPS. Corporate Communications provides handout materials. In addition, a PSPS
video was created representing the four parts of the Wildfire Plan to share with external partners, fire
agencies, customers, and others who have an interest in the Company's wildfire mitigation efforts. This
team's ongoing efforts help ensure that our outreach is broad, inclusive, and comprehensive.
Equity Advisory Group Economically
Disadvantaged
Avista is also working closely with its internal Equity Older Adults& Healthcare
L- Senior Citizens Workers
Advisory Group16 to identify Highly Impacted '
Communities and Vulnerable Populations ("Named
Communities" unique to the Company's service Marginalized
q I� y Community Equity Advisory
territory. According to Washington state, these are Members Group
-' Participants
communities that are highly impacted by adverse
socioeconomic conditions, pollution, and climate Tribal Members
change, or who experience a disproportionate risk of
environmental burdens.The identification of customer
barriers, development of workable solutions, and
implementation of an effective multilingual
16 This group is required by Washington State regulation,WAC 480-100-655(1)(b).hftps://app.leg.wa.ciovMAC/default.aspx?cite=480-100-655&pdf=true
68

communication strategy is an ongoing process but one that Avista believes to be important to the
success of the Wildfire Plan as well as PSPS planning and implementation. Avista is steadfast in
ensuring that all customers have access to programs and utility-related information especially related
to safety. These efforts will continue to be reflected in our wildfire outreach efforts going forward.
Community Response for Vulnerable Populations (CRVP) Group
Avista brought together a diverse group that includes nearly 40 representatives from organizations and
agencies that serve vulnerable populations as well as municipal departments and emergency
managers. The vulnerable populations represented by this group include refugees and immigrants,
seniors and aging populations, folks with disabilities, limited-income communities, and those with
elevated health risks. Avista invited the CRVP Group to attend a 2-hour workshop at our headquarters
focused solely on wildfire at which we shared Avista's Wildfire Mitigation Plan, provided handouts on
Public Safety Power Shutoff, and gathered information and feedback on how best to reach our
vulnerable communities with this information. This group helps us communicate with and support the
customers they represent, increasing our awareness of the needs in this area including additional
language options or outreach requirements.
Town Hall Meetings 36.000 Customers ached
;; 225 Public Safety Partners,'
Each year Avista hosts annual Telephone Town Halls that Community Leaders
y p 8 Counties in Tier 2 and 3
serve as an important communication and engagement tool
for a broad spectrum of interested parties. These live, 2023
90,000 Customers Reached
interactive events are designed to reach Avista customers 640 Public Safety Partners!
Community Leaders
and customers in adjacent utilities' service areas. 16 Counties in Tier 2 and 3
Each Town Hall provides participants with the opportunity to "� 2024
fl,
join a live conversation about wildfire preparedness. All Customers Reached
Attendees hear directly from Avista's system operations staff
and managers about the steps we are taking to reduce
Customers Reached through outreach events each year
wildfire risk in the region. Additionally, our Public Safety
Partners join the call to discuss emergency preparedness, coordination, and response efforts.
Participants can ask questions in real time and engage in live polling, offering valuable feedback that
helps shape our Wildfire Mitigation Plan and outreach strategies. These events are promoted widely
through social media and community events, ensuring that anyone—regardless of whether they are an
Avista customer or not—can sign up and participate.
69

Goals of the Town Hall meetings Dear Customer,
include sharing information on In response to dry summer conditions and increasing wildfire danger in the region,we are applying
temporary changes to power line operations in our Washington and Idaho service areas.We have
what communication to expect implemented this operational change,now called Fire Safety Mode,for over 20years.
from the utility before, during, and A key part of our wildfire strategy is the use of Fire Safety Mode,which adjusts how the system
responds to faults during high-risk weather.Unlike normal operations,where lines may attempt to
after a PSPS event, to educate
re-energize automatically,Fire Safety Mode keeps lines de-energized until crews confirm it is safe t
customers on Avista's efforts to restore power.While this may extend outage times,it significantly reduces the risk of ignition.
reduce wildfire risk, and to explain "Wildfire preparedness is notjust a seasonal effort—it's a year-round responsibility,"said Heather
Rosentrater,CEO of Avista."We've invested in infrastructure,technology,and operational practice
our strategy with elevating system that help us respond to changing conditions and protect the communities we serve.Our focus on
protection settings (Fire Safety safety is foundational to all we do"
Since launching our Wildfire Resiliency Plan in 2020,we have completed numerous grid-hardening
Mode) during critical fire weather projects in high-risk areas.These include replacing wooden transmission poles with steel,installin
events. We also ask customers to fire-retardant mesh at pole bases,and upgrading wooden crossarms to fiberglass.In certain areas,
we will be converting our overhead powerlines to underground service to further reduce the risk of
update their contact information if wildfire.We have also expanded vegetation management to reduce the risk of trees contacting
they need specialized assistance. power lines.
In the most extreme conditions,we may implement a Public Safety Power Shutoff(PSPS)a
targeted,temporary outage in areas facing severe wildfire risk.PSPS is a last-resort measure,used
Community and L oca/ only when weather conditions such as high winds and low humidity create a heightened threat.
Avista crews patrol affected lines before restoring power,and Community Resource Centers may
be activated to support customers during extended outages.
L ea ders What you can do:
Community leaders are a key part Make sure your information is up to date with Avista.We want to be able to reach you about
potential outages.Visit myavista.com to update your account information or call customer
of providing customer level service at(800)227-9187.
support. These leaders are invited Let us know ifyou have medical devices that rely on electricity.Your information will be
added to a list of customers who receive extra notifications in case of an extended outage.
to participate in Telephone Town Learn more at myavista.com/medicalequipment.
Halls alongside Avista to help Be prepared for outages.Keep your emergency supplies together in one place,like
flashlights and back-up portable chargers.Make sure you have a few days'supply of shelf-
answer questions from their stable food and water for all people and pets in your home.Learn more at
constituents and to gain the myavista.com/outages to create your own to-do list in case of an outage.
knowledge needed to lead
Avista will return the distribution system to normal as soon as weather permits and fire potential
customers through an outage decreases.We appreciate your patience and understanding during this time.
event.They work together with You can read about our plans and howyou can be prepared at myavista.com/wildfire and watch
Avista to prepare citizens for watch our video below to learn more
outages and to provide support and
services. They assist us in Avista notifies customers when we enter Fire Safety Mode operations
identifying libraries, schools, and/or
businesses where we are able to host Community Resource Centers for customers during PSPS events.
They also provide Avista with a primary contact for PSPS events in communities or neighborhoods.
70

Community Response Ambassadors
In 2023 Avista launched an employee team of volunteer Community Response Ambassadors who train
with the Red Cross to provide help and support to our most vulnerable customers, especially during
outage events. These volunteers also staff our Community Resource Centers to help customers during
PSPS events.
Community Events
Avista attends community events throughout our
service territory sharing the message around our
Wildfire Plan mitigation efforts and Public Safety
Power Shutoffs, distributing materials on wildfire or 1
resiliency and PSPS, and answering questions. In 2024 — —
and 2025 we met with several county local emergency
management organizations, County Commissioners, u �
cities, fire professionals, public health providers,
schools, the Red Cross, Tribes, critical service • -
providers, and more. We attend a variety of safety fairs
and public events across the service territory. This
includes providing presentations to various groups and
organizations and hosting an information booth at
events, providing the opportunity to interact with a
host of community service providers. For example, in
2024 we attended the Community Response for Vulnerable Populations event, which includes Spokane
County, Spokane Transit Authority, Washington State Dept. of Transportation, Spokane Regional
Health District, Aging and Long Term Care of Eastern Washington, Spokane Neighborhood Action
Partners, Disability Action Center Northwest, and the International Rescue Committee.
Vulnerable Customer Outreach
In 2022 we began an effort to better identify and support our most vulnerable customers. Avista
makes a concerted effort to help overcome customer barriers and utilize a multilingual and
multichannel communication strategy to reach these customers, including engagement with
community support organizations across the service territory that help us identify needs and gaps.
Avista also has a specialized Customer Assistance Referral and Evaluation Services (CARES) team within
the customer contact center who provide specialized support to customers, specifically connecting
customers with resources such as food, housing, and medical care as well as providing direct support
during PSPS events. Medically vulnerable customers may be provided with battery backups or
advanced notice on outages as discussed above in the PSPS communications section of this report.
71

Specialized Outreach
Our communications have evolved over time as we
continue to learn more about our customer base and how
to reach more people with our preparation and safety
messages.
� i
We have identified that 5% of Avista customers speak a r'
primary language other than English, and of those, 95%
speak Spanish as their primary language. In response, nnaHN .
Avista developed a varietyof materials in Spanish which ° d� 07 "10 eHHHH ne egonacHOcrHnpH
p p '"°ti •6yue,A� 03Hepr,44
are distributed through our outreach channels and =
community events. m'° ••'Y'"' °"`° °�.° °
Telephone Town Halls We are also working on
including additionalAd Campaigns �. Syr,.•
languages. In 2024 Telephone
SpanishTown Hall events offered
� �`°'°�'=c °. Avista
either Russian or Spanish. b
outreach
Outage Map There were 79 customers that
Printed Materials materials
identified as Russian, and for Spanish, 1,192
PSPS Outreach customers, providing a total of 1,271 non-English speaking customers.
El Mercadito Booth We also have a language line option for customer service so that customers can
speak to someone in their own language.
Spanish-specific
outreach Another specialized focus is for those with hearing impairment. For example,
our wildfire related safety videos are subtitled. We are working with the
Washington State Dept. of Social and Health Services (DSHS) and the Office of Deaf and Hard of
Hearing to further our outreach to this audience and learn how to best translate our messages into
American Sign Language. Avista presented its then-Wildfire Resiliency Plan to approximately 80 staff
from DSHS and then collected feedback and answered questions, especially related to customer
support around potential PSPS events. Avista is remaining in contact with DSHS to continue to refine
and improve our communications in this area.
72

LESSONS LEARNED & PLAN UPDATES
The Idaho Legislature and Commission requested that we provide:
"An update of lessons learned from the previously approved WMP within the annual filings for
WMP review and approval."
Avista's Wildfire Mitigation Plan (formerly known as Wildfire Resiliency Plan) is built upon the concept
of Plan-Do-Check-Adjust. We are continually evaluating the efficacy of our programs and updating and
revising strategies to incorporate lessons learned, new information related to fire risk, utility best
practices, and in response to feedback from customers, agency partners, regulators, and others
including fellow utilities. Avista adapts business strategies, plans, and processes to align with changing
business and physical climates. Many of our improvements have involved enhanced customer
engagement and support, constant work to improve our modeling, risk analysis, and technology,
incorporating new technologies such as wildfire cameras and digital data, increasing customer
protection measures such as Public Safety Power Shutoffs, and refining practices related to our Fire
Safety Mode operations. Some recent improvements made are listed below. Details about them can be
found within the body of this report.17
Communications
• Increased and enhanced our wildfire-related customer communications efforts, specifically with
customer engagement activities such as the town hall meetings, which have been expanded to
all 16 counties in our service territory.
• Added additional language options (with Spanish being a focus based on our customer base) to
our communication outreach, as well as translating our messages into American Sign Language
and providing subtitling to allow us to reach more customers. We continue to research
customer communication needs and how to reach as many as we can.
• Lessons in communications involving Fire Safety Mode (FSM) and PSPS were learned in 2024 as
we experienced our first PSPS event. Our interactions with customers helped us see that our
engagements with them on both of these issues was causing confusion. We have refined our
communication plan to only notify customers during PSPS outage, when power will inevitably
be lost.
• Updated our PSPS tabletop exercises to include more parties including first responders and
emergency responders who serve both Avista service territory and adjacent utility service
areas, land management agencies that respond across both Avista's service territory and
contiguous jurisdictions, and Tribal governments and Tribal emergency response personnel.
17 Note that this information is more extensive due to this being the first of our new Wildfire Reports as aligned with legislative edict,and the first time
many in the broader audience will have seen it.Going forward this will be limited to the year-to-year enhancements and improvements.
73

• We are in the process of adding a Partner Portal, an automated communication system related to
Public Safety Power Shutoff events. The functionality of this portal is described in above
sections
Customer Support
• Created a Community Response for Vulnerable Populations During Outages (CRVP) Group which
includes nearly 40 representatives from organizations and agencies that serve vulnerable
populations (as well as municipal departments and emergency managers) to inform them of
our Wildfire and PSPS plans and strategies and to gather information/feedback on how best to
reach our vulnerable customers with this information as well as working with them to develop
strategies on how we can jointly support the people they serve through PSPS events.
• Supplemented support for our most vulnerable customers using our Customer Assistance
Referral and Evaluation Services (CARES)Team, a specialized team within Avista's customer
contact center that focuses on this work, acting as a liaison between the customer and
community partner support networks. This includes specialized outreach to life support
customers with the Battery Backup Program and through direct contact with them if a PSPS
event is possible, even including sending local first responders to their homes if they cannot be
reached.
• We also launched an employee team of volunteer Community Response Ambassadors who
trained with the Red Cross to provide additional help for customers, especially during outage
events. These volunteers also staff the Community Resource Centers.
• Developed outreach specific to area Tribes, including working with them to identify their specific
needs and vulnerable populations including Tribal elders and medically vulnerable Tribal
members to help support them in case of an extended power outage. Working with them to
identify Community Resource Center locations in their areas.
• Worked with Avista's Equity Advisory Group to fully develop and identify Highly Impacted
Communities and Vulnerable Populations ("Named Communities")18 unique to the Company's
service territory to allow working through the barriers specific to this customer group in wildfire
education, preparation, and support.
• Avista's Social Impact Team has become an integral part of PSPS events, acting as the primary
liaison between customer support partners and Avista. This team provides timely updates and
'$Washington State Department of Health,"Instructions for Utilities to Identify Highly Impacted Communities,"Instructions for Utilities to Identify Highly
Impacted Communities I Washington State Department of Health Idaho overburdened and underserved areas can be found on the Climate and Economic
Justice Screening Tool:Explore the map-Climate&Economic Justice Screening Tool(geoplatform.gov)
74

information sharing specifically related to customer support agencies. They actively educate
these partners about Avista's wildfire efforts, Fire Safety Mode operations, and Public Safety
Power Shutoffs to help ensure community resilience and customer support. They also help the
agencies align resources with real-time community needs during an event. They also deploy the
Company's Community Resource Ambassadors to Community Resource Centers and coordinate
this with the Red Cross. They ensure that all of the needed resources are deployed.
• Developed the ability to quickly identify and contact life support customers for specialized
support and outreach by adding a life support customer flag to all the feeder lists.This allows
Avista to proactively call these customers to make sure they are aware of wildfire threat and
potential outages and provide options for support.
• Created a program to provide a battery backup power system to customers who have been
verified through their primary care physician as having 24-hour dependency on medical
equipment, greatly decreasing the unique impact of a PSPS on these customers.
• Completed identification of critical commercial and industrial customers and service providers for
notification during elevated Fire Safety Mode protection settings or in the event of a PSPS.
These are customers who provide critical support services to society such as police and fire
stations, large airports, traffic control, communication towers, etc.
• Implemented a comprehensive PSPS outreach program. In 2024 the Company reached out to
over 14,000 first responders, emergency managers, critical customer groups, service providers,
healthcare organizations, city and county leaders, state agencies, and others to provide
education around our PSPS Plan and to strategize about protecting and supporting customers
through potential outages, both across our service territory and in contiguous jurisdictions.
Improving Tools & Technology
• Continually improving the inputs to our WUI map by updating information we use from the USDA
(both the Housing Unit Impact and the Wildfire Hazard Potential data as mentioned previously)
to help us more clearly and specifically include structural and human impact as well as areas
where fires may be particularly difficult to control. This new data further enables our ability to
identify the areas of highest risk in our service territory. It is updated into our model as it is
updated and becomes available.
• In acquiring digital data for both the transmission and distributions systems to identify risk trees,
we are becoming familiar with the large amount of data these tools provide and how to use all
this information to focus our vegetation efforts in areas that should provide the most positive
impact and risk reduction. We believe that these tools are helping us plan vegetation work in
75

the areas of greatest need with accuracy in a more precise and predictable way, streamlining
our vegetation management programs and helping to maximize their value.
• Risk Model —Cost/Benefit Modeling. We are in the process of developing a comprehensive
wildfire risk modeling decision support tool. This tool can calculate risk reduction more
accurately than our existing Dashboard by including scenario planning and a matrix of
treatment solutions. It will incorporate asset fragility analysis, probability of ignition, fire
consequence modeling, the valuation of economic impacts, and finally, monetizing the value of
wildfire-related mitigation techniques such as grid hardening, PSPS, increased vegetation
management, and/or combinations thereof. A new dashboard using near real time weather
data will be available during fire weather season to make more informed decisions. It will also
provide cost/benefit analysis for each of our wildfire programs. Information from this tool
should be available during the first quarter of 2026.
• The use of drones in assisting with inspections and patrols, especially after a PSPS event, helped
speed up the process, especially in areas where it is difficult to get vehicles to the structures to
have eyes on the situation.
• We learned the value of weather stations located near extreme weather events, as they provided
real-time information that helped us gauge the intensity of weather events that lead to
increased fire risk and to improve our decision-making around whether to implement a PSPS.19
In 2025, we began the installation of utility owned weather stations across our network.
• 10 cameras were installed in 2024 with 5 more installed in 2025. The advanced notice afforded by
these cameras increases the likelihood of timely containment and suppression of wildfires,
saving lives and reducing property losses. They are valuable in quickly identifying a fire start as
well as its precise location, enabling resources to be dispatched directly to the latitude and
longitude of the smoke so firefighters do not have to search for the fire, saving valuable time.
We partnered with the Washington Dept. of Natural Resources and the Idaho Dept. of Lands in
identifying locations for wildfire identification cameras in high-risk areas of our service territory.
New Programs & Stra tegies
• Avista initiated our first wildfire-related undergrounding project in 2025, selecting a feeder in
Southeast Spokane,just outside the city limits but in a WUI Tier 3 high-risk fire area, to better
understand how the undergrounding process would work. This feeder was on the Company's
"risk list" and was placed into Fire Safety Mode multiple times in 2022 and 2023, providing
proof of its hazardous status. It serves about 190 customers in a semi-rural area, with 11 miles
of two and three phase laterals. When this project is completed in the fall of 2025 we expect to
19 Until our local weather stations are fully operational,we have deployed handheld devices with field personnel to capture weather information.
76

learn the actual average cost per mile, complexities around right-of-way and permitting
processes, constraints, impacts, and more.
• In 2025, Avista is rebuilding a section of distribution line in a high fire risk area to learn about the
construction, cost, constraints, etc. of adding covered conductor to our distribution system. We
should be able to report on this project in 2026.
Expanding & Improving Existing Programs
• Extended our Safe Tree Program, which works with customers directly to remove risk trees on
their property, into all WUI 2 and WUI 3 areas across the service territory and added a platform
to the Company's website for this program. The website allows customers to request Safe Tree
work directly (if they are qualified), communicating with arborists directly to schedule this work
at their convenience.
• Beginning in 2026, Avista will begin using Aerospace Technical Services (ATS) as a decision-
support tool to enhance wildfire preparedness and response. ATS will help model potential fire
scenarios, evaluate system vulnerabilities, and inform operational decisions such as PSPS
implementation and resource deployment. This data-driven approach will strengthen our ability
to anticipate risk, improve coordination, and refine mitigation strategies. Prior to the start of
fire season in 2026, the new model will be integrated into our processes and will replace the
existing wildfire dashboard.
• Created a strategy to prioritize steel transmission pole replacements in the highest risk areas
based on a spectrum of inputs including actual historic fires and topography, moving beyond
utilizing WUI zone alone.
• PSPS—We initiated our first PSPS in 2024. The lessons learned from that experience are detailed
in the PSPS plan attached as Appendix A.
• For the 2025 wildfire season, Avista added non-reclosing protection schemes as well as de-
energization of 115kV transmission lines during critical fire weather conditions. See Appendix A
• Enhanced Transmission Grid Hardening—The Company is prioritizing remediation work found
during routine inspections of the transmission system with wildfire funding to accelerate
maintenance issues that are identified.
Operational Improvements
• We are continuing to refine and enhance Fire Safety Mode operations to provide a
comprehensive scale of risk reduction based upon actual conditions. We are utilizing actual
77

experience to refine and improve our understanding of when to employ fire safety mode
settings.
• Developed a robust Emergency Operating Procedure (EOP) related specifically to PSPS. Created
realistic EOP annual tabletop exercises that include external partners, such as the Red Cross,
Washington DNR, and IDL to practice wildfire response in a coordinated, consistent, efficient
manner.
Enhancing & Expanding Partnerships
• Through Expanded the Fuel Reduction Partnership program beyond Washington state to include
engagement with the IDL, the U.S. Forest Service, the Nez Perce Tribe, and local and regional
fire agencies across our service territory.
• By engaging with first responders such as the Washington DNR and the IDL, we created Expedited
Response Agreements that cover nearly 99% of our service territory.
• Continuing to actively seek out and build valuable partnerships and connections to support our
wildfire efforts with both external partners and customers, including working with and learning
from our utility peers to strategize and develop best practices.
• Through development of our Partner Forum, PSPS tabletop exercises, and, in 2026, our Partner
Portal, we continue to enhance communications with external partners, critical service
providers, and customer support partners, especially during outage events.
Verifying Our Programs
• Worked with a third party to validate the effectiveness of our Vegetation Management Programs
and to increase efficiency in our vegetation management cycle for our service area. This
analysis determined that Avista has a reasonable and responsible approach which is aligned
with "best-in-class" vegetation programs of other major utilities, and that our one-year Risk
Tree inspection cycle is aligned with industry best practices, as are our WUI Tier designations.
More information about this study can be found in the Vegetation Management portion of this
report.
• Worked with a third party to perform a cost-benefit analysis of undergrounding existing overhead
distribution facilities in high fire risk areas. The analysis included assessing criteria including
customer impacts and outage and other costs related to undergrounding existing overhead
conductor in areas identified as being at high risk. The details of this study are located in the
Distribution Grid Hardening part of this report.
78

GLOSSARY OF TERMS
Asset: Electric lines, structures, equipment, or supporting hardware in the service of providing electric
power to customers.
Brush: Refers to vegetation dominated by shrubby, woody plants or low growing trees.
CARES: Customer Assistance Referral and Evaluation Services is a specialized team within Avista's
customer contact center that supports our most vulnerable customers, assisting with resources such as
food, housing, medical care, and battery
backup systems. power plant transmission lines carry
generates electricity electncity long distances
distribution lines carryr� electricity to houses
Circuit: The path for transmitting electric
current from the device that creates the
current (generator) across all associated
transformers on poles
equipment (such as the wire or conductor, stepdownelectnary
transformer steps nei hborhood before it enters houses
switches, transformers, breakers, etc.) to up voltage g
9 transformer steps
the end user, as shown in the graphic. transmission down voltage
Circuit Recloser: A circuit recloser is an automatic switch that shuts off power when a fault is detected
and restores it if the issue clears. With communication capabilities, it can be remotely monitored and
controlled. During high fire risk, Avista can configure reclosers to stay open after a fault, preventing re-
energization and reducing ignition risk.
Community Response Ambassadors (CRA): An Avista employee team of
volunteers that support Community Resource Centers in the event of a i iA
PSPS.
Conductor: The wires or lines suspended from towers or poles that help
electricity to pass from one location to another, generally made of
aluminum reinforced with steel or composite materials, though some low
and medium voltage conductor is made of copper. r//j I
Critical Facilities/Infrastructure: Essential services and systems vital to public safety and utility
operations, including emergency services, healthcare, water, communications, and key grid
components. These are prioritized for power restoration during outages.
Crossarm: A crossarm is a piece of hardware providing an attachment point
for insulators to support the loading of overhead conductors. The crossarm r•- "
is typically made of wood, steel, or fiberglass.
Transmission crossarm
79

Cutout: A "C" shaped insulated device with a tubular fuse that disconnects part
of a power line when current exceeds safe levels. It helps isolate faults, enables cutout
maintenance, and prevents outages from spreading. ~
Cycle Trimming: A routine vegetation management practice where sections of
the electrical system are inspected and trimmed on a rotating basis. In higher-
risk areas, additional inspections may be added to identify and address "Melt-
potential wildfire hazards.
Y tube.
Dispatcher: A person who coordinates outage response by confirming
locations, assigning crews and equipment, and sharing information to support effective repairs.
Distribution (DX): Electric facilities that have a voltage that is 60 kV or lower.
Distribution Automation: Part of Avista's Wildfire Program, this initiative upgrades grid devices to
support remote monitoring, automated operation, and dynamic protection settings during fire season.
Distribution Grid Hardening: Avista's program to strengthen power lines in high fire-risk areas by
upgrading materials, replacing aging infrastructure, and reducing ignition sources through targeted
improvements like wildlife guards, modern conductors, and selective undergrounding.
Distribution Infrastructure Upgrades: Improvements to Avista's distribution system aimed at reducing
spark risk and increasing resiliency. These include replacing aging or spark-prone equipment, installing
wildlife guards, and using more fire-resistant materials. Also referred to as Distribution Grid Hardening.
Dry Land Mode (DLM): Renamed Fire Safety Mode.
Elevated Fire Threat Areas: These are WUI Tiers 2 and 3.
Emergency Operating Procedures (EOP): An internal command structure that shifts normal operations
to emergency response.
Equity Advisory Group: Avista's specialized team that is working specifically with vulnerable customers
and Named Community members to identify barriers and develop workable solutions for their needs,
including multilingual communications and ensuring accessibility to programs and materials.
Expedited Response: In Avista's Wildfire Plan, this is an agreement with state, local, and regional
firefighting agencies to send fire crews directly to the site of a transmission trip during fire season
event so if the fault results in a fire, it is managed immediately.
Extreme Wildfire Risk:This means that based on existing weather and vegetation conditions, a large,
rapidly growing wildfire is possible should ignition occur.
80

Fault: A fault isan abnormal condition present on
the power system, usually a short circuit caused
by lightning, tree contact, windblown object in '
the lines, or other similar problem.
Fau|t Reduction: Reducing the number of /'-��
m o
electrical faults by strengthening infrastructure
through reliability programs, especially inareas
with higher wildfire risk
Feeder: Adistribution circuit originating from a
substation, consisting of three-phase main line that branch into laterals delivering power to customer
service lines. Avista uses short main trunks with longer laterals to efficiently serve customers.
Fire Behavior: The manner in which a fire reacts to the influences of fuel, weather, and topography.
Fire behavior provides an indication to firefighters on how to best battle the blaze.
Fire Behavior Index: A scale that captures fire severity as a function of flame length (intensity of burn)
and rate of spread.
Fire Front:The part of fire within which continuous flaming combustion is taking place. The fire front
is usually assumed to be the leading edge of the fire perimeter. In ground fires, the fire front may be
mainly smoldering combustion.
Fire Ignition Events: When a spark is created by the interaction of utility equipment and its
surroundings (such as when a tree falls into a powerline) and results in a spark that, under certain
circumstances, could become afire.
Fire Mesh Wraps: wire mesh treated with inturnescent graphic that, when
exposed to extreme heat, rapidly expands to form a barrier between the fire and
the wood pole. These wraps help prevent low-burning fires from accessing wood
poles, protecting them from damage ordestruction.
Fire Perimeter: The entire outer edge or boundary of fire.
A piece ny fire mesh
wrap
Fire Risk Potential: This incorporates weather and fuels information to rate the overall fire threat at a
particular location as well as fire's likely behavior should one start.
Fire Safety Mode (FSM): Formerly called Dry Land Mode, Fire Safety Mode isa non rec|osing
distribution protection scheme used during summer fire season Under Fire Safety Mode operations,
rec|osing is limited or not allowed to help prevent equipment from failing and creating a spark, thus
focusing on safety.
81

Fire Safety Mode Automation: Avista's plan to upgrade midline and substation devices determined to
be in elevated fire risk areas to enable these devices to be operated remotely and automatically in
response to fire situations.
Fire Safety Mode Ready Devices: Midline and substation devices located in high-risk fire areas that
have been upgraded or replaced to allow protection settings to be operated remotely and
automatically in reaction to wildfire or wildfire risk situations.
Fire Season: The time of year that wildfires are most likely to take place for a given geographic region
due to seasonality, historical events and weather conditions, vegetative characteristics, etc.
Fire Threat Areas: Areas which have higher likelihood of impacting people and property and where
additional action may be needed to reduce wildfire risk. Threat level is based on elements such as
population, topography, vegetation type, and historical fires in the area.
Fire Threat Conditions/Fire Danger Rating:This considers current and antecedent weather, fuel types,
and both live and dead fuel moisture to estimate the likelihood of a fire occurring as well as potential
fire behavior should a fire occur.
Fire Weather: Weather conditions that influence fire risk, ignition, behavior, and suppression.
Fire Weather Dashboard: This is Avista's MAX FIRE RISK
primary means of determining fire risk ©, FR d' FRi°3
./ FR:49
across our system. It is a risk-based
FR:4.2 - FR-.4.1
computer program that combines the 7-day
5.7 FR<� or
weather forecast with equipment
FR 46
MAX WIND SMM FR:2.2
performance and fire risk levels based on FR,A FR,2 FR,6FR`00 FR 26
time of year, drought conditions, type of FR'd
FR.0.]
vegetation and moisture levels, sustained
FR.].1
winds, wind gusts, and more. It indicates the 25.3 FRT.0
risk level on each of Avista's distribution
circuits for the upcoming week and M � NWSWARNINGSp^
highlights the maximum expected daily risk 'tl
for every feeder on Avista's distribution and
transmission systems. Fire Weather Dashboard screenshot
Fuel: Combustible material. Includes, vegetation, such as grass, leaves, ground litter, plants, shrubs,
and trees that feed a fire.
Fuel Concentration/Density: Mass of fuel (vegetation) in an area which could combust in a wildfire.
Fuel Management: Removing, thinning, or otherwise altering vegetation to reduce the potential rate
of propagation or intensity of wildfires.
82

Fuel Moisture Content: Amount of moisture in a given mass of fuel (vegetation) measured as a
percentage of its dry weight.
Fuel Reduction: Manipulation, including removal of fuels (vegetation
management)to reduce the likelihood of ignition and/or to lessen
potential damage and resistance to fire control. ^ "
Fuel Reduction Partnerships: In Avista's Wildfire Plan, this is partnering
with external land management agencies, leveraging funding to remove 1 � <
fuels near Avista facilities. Sharing the cost allows both parties to do more`
work than each could accomplish with individual budgets.
Fuel Reduction Efforts
Fuse: A device that limits the amount of current flowing through the circuit.
The fuse is constructed with a small piece of metal that, when exposed to high
current typically caused by a fault, melts and interrupts the flow of electricity.
Fuses are typically placed on lateral tap lines off the main circuit.
Grid: A network that generates, Fuse
O Generation O Transmission
transmits, and distributes electricity
III Transmissionime to consumers. It is a complex system of power plants,
transmission lines, substations, and distribution networks
Power station Tramformer
that ensures a reliable flow of electricity from generators to
P—dine homes and businesses.
® O Distribution
Substation
Posrerline O Consumption
Home Commercial facility
83

Grid Hardening: Actions such as equipment upgrades,
maintenance, and planning, taken in response to the risk Fiberglass with polymer ribs insulator_
of undesirable events (such as outages or wildfires) or Eyebolt
undesirable conditions (such as old or unreliable ►� Hot clamp
equipment) of the electrical system in order to reduce or
Bracket
moderate those events and conditions based on relevant /
Lightning arrestor
risk drivers or factors. This is a way of providing reliable
energy for customers. In the Wildfire Plan, this
specifically means adapting transmission and �:-y Disconnect switch
distribution materials and construction to minimize the
potential for utility-involved fires in addition to 1
protecting utility infrastructure in the event of a fire.
Herbicides: Typically used on the right-of-way to control incompatible tall growing species and noxious
weeds. For the past several years, at Avista herbicide applications have primarily consisted of treating
the stumps of fast-growing deciduous trees after they are removed to prevent resprouting. These
applications are recorded within the same work records as the tree removals which are generally
categorized as risk tree work.
High Canopy: Forested areas with tall, mature trees. In these
types of areas, fire can spread from the ground into the tree
tops, where it becomes difficult to control. In relation to utility
infrastructure, this high fire can access the tops of poles and
structures and burn them down to the ground. Thus, replacing
more burnable wood poles with steel helps protect poles from
this type of high level fire. `" - s
High Canopy Fire near the Noxon-Pine
Creek transmission line in 2023
High Risk Fire Areas: Areas in Avista's service territory that have
been identified as having increased risk for wildfire and associated damage; locations in wildland urban
interfaces (WUI zones) for which there is little or no fire protection (typically rural or remote areas), or
which have experienced historic wildfires. The Company includes several factors in determining areas
of high risk, as described in the WUI section of this report.
High Wind Advisory or Warning: Level of wind risk from weather conditions as declared by the
National Weather Service (NWS). The difference between a high wind advisory and a high wind
warning is the level of winds associated with the event. Advisories go into effect for sustained winds of
40 mph or less with gusts of at least 45 mph. Warnings are issued if sustained winds are above 40 mph
and gusts are 50 mph and above.
Highly Impacted Communities: As defined in Washington State, highly impacted communities must
meet at least one of the following criteria: are within the limits of a reservation, and/or suffer
84

environmental health disparities such as pollution, hazardous waste, poverty, or cardiovascular
disease.20
Hot Line Hold: A hot-line hold is an assurance to the utility worker that an automatic protective device
has been set to not reclose in the event the line or equipment becomes de-energized, typically used
when line crews are working on a powerline or power equipment issue. With a hot line hold, the
applicable device will not be re-energized until the appropriate dispatcher determines workers are in
the clear. A hot line hold pertains to energized lines or equipment. In this configuration, auto reclosing
is disabled, and instantaneous tripping is enabled to protect workers.
Hot Tap: This is a connection to the utility's powerline. It is typically used to link transformers to power
lines, for making distribution connections at line taps, making repairs, and creating attachments. The
traditional hot line tap is attached via a bolt. These
connectors allow adding new service connections,
bypassing lines, or making repairs. Avista is adding
�J ro
wedge connected stirrups which attach in such a way _ t
that if the connection loosens or if the stirrup melts, the
conductor is held in place and does not fall to the
ground.
Hot Tap Connectors
Incident: In the wildfire arena, this is a human-caused or natural occurrence, such as wildland fire,
which requires emergency action to prevent or reduce the loss of life or damage to property or natural
resources.
Incident Command Structure (ICS): The combination of facilities, equipment, personnel, procedures,
and communications operating within a common organizational
structure to effectively manage an incident. The ICS provides a
standardized approach to the command, control, and *.
coordination of emergency response, providing a common 'Qr
hierarchy within which all responders (including Avista) can
work together.
8rd, !
InciWeb: This is the Interagency All-Risk Incident Information 1�
Management System that provides a single source for fire
incident related information and a standardized reporting tool
for public use. Fire information is available for events across the :S }
U.S. o,
Infrastructure: This refers to the equipment Avista utilizes to ,
20 Washington State Dept.of Health,"Instructions for Utilities to Identify Highly Impacted Communities,"Instructions for Utilities to Identify Highly Impacted
Communities I Washington State Department of Health
85

serve customers, including poles, transformers, conductor, switches, substations, etc.
Inspection: The act of examining utility assets, equipment, or infrastructure to assess their condition,
functionality, compliance with standards or regulations, including encroachment concerns from
vegetation or other external sources. May be performed via foot, vehicle, or aerial.
Insulator: Insulators keep the electrically charged line from touching
the poles or towers so the line can continue to transmit and is not
grounded. Insulators must be strong i
' 01
enough to withstand the weight of thelip
conductor and the potential stress of the
electricity wanting to connect to the earth. -
They are designed to be non-conducting, Dead-end Insulators
Many insulators are designed with an
Strings of transmission insulators, umbrella or petticoat at the top to keep the lower part insulated from
sometimes called bells the rain.
21
Insulator Pin: This is a piece of overhead hardware that fastens the insulator to
the crossarm. The insulator pin is bolted through the crossarm and the
insulator is screwed onto the top of the insulator pin.
Insulator with pin
IVR: Interactive Voice Response is a technology that allows telephone users to
interact with a computer-operated telephone system with voice recognition
technology. It allows automatic call distribution, allowing the Company to reach out to multiple
customers at the same time.
Vertical Fuel Arrangement
Ladder Fuels: Fuels which provide a vertical path between the
ground and higher vegetation, allowing fire to carry from surface
fuels into the crowns of trees or shrubs with relative ease. These
fuels help initiate and assure the continuation of crowning where
the fire spreads very rapidly from treetop to treetop, becoming Y
much more difficult and dangerous to control. _
Ladder Fuel Diagram
21 For additional information,see:Glossary of Insulator Terms(insulators.info)
86

Lateral: In the distribution system, these are lines that breaks _ .'.'�' • �'
-ter.
off from the main feeder trunk (that comes out of the v- _
substation) to deliver electricity to customers (service lines). Y
The laterals normally have fuses to separate them from the �—
mainline if they are faulted.
HDAR: Light Detection and Ranging, sometimes called 3-D laser scanning, which can be used to make
high resolution representations of the earth's surface. At Avista it is used on
UDAR Image the transmission system to identify vegetation encroachment and risk trees.
It works well for transmission due to the open linear transmission rights-of-
way. LiDAR is primarily collected via helicopter and fixed wing aircraft.
-axe
Lightning Arresters
Lightning Arrester: A piece of hardware that reduces voltage surges
from direct or nearby lightning strikes. When a lightning strike occurs,
the overhead conductor experiences higher than normal voltage levels.
This high voltage is dissipated via the lighting arrester, mitigating
potential damage to equipment.
Line Miles:The number of miles of transmission and/or -
distribution line. Differs from circuit miles because - -
individual circuits, such as the two circuits of a double- 1Circuit Mile
8 Line Miles
circuit line, are not counted separately in circuit miles
but are counted as separate in line miles.
87

Live Fuel Moisture Content: Moisture content within living
vegetation, which can retain water longer than dead fuel. LIVE FUEL MOISTURE CONTENT
Moisture content is a critical factor related to how much
fuel is available to burn in a wildfire. When moisture
MOISTURE CONTENT GRASSES TREES/SHRUBS
content in living vegetation reaches a critical low threshold, 150-300% GROWING CYCLE GROWING CYCLE
fire danger increases. 120-150% RESIST SPREAD RESIST SPREAD
L100-120% RESIST SPREAD RESIST SPREAD
Managed Risk: In Avista's Wildfire Plan this is the future 0% BECOMING LESS BURNA GESSIVELiRESISTANT TO SPREAD BURN AGGRESSIVELY
°� FUELS CONTRIBUTE CONTRIBUTESTOstate wildfire risk level as it is impacted by the addition of TO SPREAD FIRE INTENSITY
% COMPLETELY CURED DORMANT,LEAFLESS
Wildfire Mitigation elements like grid hardening. DEAD FUELS DEAD FUELS
Medical Baseline Customers: Residential customers with qualifying medical conditions and/or who are
dependent on power for qualifying medical devices for certain medical needs.
Sectionalizing Midpoint
Midline (Midpoint) Circuit Reclosers: Often used on long _ recloser recloser
distribution lines where substation-based equipment cannot 4M
! 0
adequately protect the entire length of the circuit. Avista's Fault
Wildfire Plan adds communications to these midline circuit recloser 0
reclosers to provide monitoring and control functionality,
including the ability to operate the device remotely. By —Q
placing automated midline circuit reclosers at strategic Sectionalizing Midpoint
locations, Avista Distribution Operations can re-task devices recloser recloser
during periods of elevated fire danger to operate in fire protection Recloser Diagram
mode
Miles Completed: In the Avista Vegetation Management Plan, this is a calculated value that equates to
the known overhead line mileage within a work polygon multiplied by the percentage of planned
trimming, removing, replacing, and other vegetation management work completed within that
polygon. Completion of planned work means performing such vegetation management to the
Company's specifications.
Miles Inspected:The number of miles of utility assets, equipment, or infrastructure examined to
assess their condition, functionality, compliance with standards or regulations, including encroachment
concerns from vegetation or other external sources. May be performed via foot.
Miles Planned: In Avista's Wildfire Mitigation Plan, this is the number of miles of risk tree inspections
projected for completion.
88

Momentary Outage: The IEEE defines
"momentary' outages as a brief loss Why outages
Construction work
of power (less than five minutes in O Weather may occur:
length) caused by the opening and �N•
closing operation of an interrupting
device. Animals in the system
Multi-Agency dons_
Communities
Coordination/Partnerships: A �_ 'EMERGENCY
yy �YA AGEMEN7
generalized term which describes the
TIIBES _
Ell °
functions and activities of _ °
representatives of involved agencies ORTURRL ERE
mmm
\ RESOURCES mmm m mmm
�mm mmm
t
and/or jurisdictions who come together to = "V-�c �►
SN GTON �•
WATER
make decisions regarding the prioritizing of � �„,�,,,,ks • / °'� �1 �
incidents, and the sharing and use of critical
resources. It also refers to agencies who work V
together, sometimes via financial assistance, Some of Avista's wildfire Partners
in reducing fire risk.
Named Communities: According to Washington State, these are communities that are highly impacted
by adverse socioeconomic conditions, pollution, and climate change, or who experience a
disproportionate risk of environmental burdens. They are comprised of a combination of "Highly
Impacted Communities" and "Vulnerable Populations" (each defined elsewhere in this report).
National Weather Service: An agency of the United States federal government tasked with providing
weather forecasts, warnings of hazardous weather, and other weather-related products to
organizations and the public for the purposes of protection, safety, and general information. Most of
its products are in the public domain and available free of charge.
Open Wire Secondary Districts:Three conductors with 120/240 volts that run pole to pole below the
primary conductors (primary conductors are on top of the pole in an overhead distribution system).
Called "open wire" because the three wires are clearly visible as opposed to a design in which the three
conductors are bundled together. Sometimes called "Secondary Main."
Operations and Response: Many of Avista's circuit breakers cannot be remotely operated and require
manual intervention to make changes to settings or to identify an issue. This may take several hours
depending on location and crew availability. Avista's Wildfire Program funds communications and
control equipment that will help us have "eyes" on critical equipment out in the field as well as be able
to control and adjust equipment remotely in case of fire or high fire threat conditions. This area of the
Plan also includes Fire Safety Mode operations, PSPS, Expedited Response, and partnership activities
including cross-training.
89

NIFC/National Interagency Fire Center: Located in Boise, Idaho, this is the home to the National
Interagency Coordination Center (NICC) and National Multi-Agency Coordination (NMAC) groups,
which provide unified guidance to fire agencies, coordinate fire response, manage firefighting
resources, and track and document fires, sources, size, and impact across the United States.
Patrol: In Avista's Wildfire Plan, this refers primarily to verify trouble where an inspection may have
identified a concern or referring to the necessary work after a fault in elevated Fire Safety Mode or
after a PSPS event. Patrols may be completed via ground, vehicle, or aerial.
Peak Fire Season: That period of the fire season during which fires are expected to ignite most readily,
to burn with greater than average intensity, and to create damages at an
unacceptable level.
Plan-Do-Check-Adjust: A continuous improvement technique also known as
the Deming Circle or Shewhart Cycle. Avista's Wildfire program uses this
technique to help continue to grow and improve the program.
Planned Outage: Electric outage announced ahead of time by the utility ;
typically to perform maintenance or repairs or to build new infrastructure.
Pole Wraps: Avista uses Genics Fire Mesh, a wire
mesh treated with an intumescent coating that,
when exposed to extreme heat, rapidly expands
to form a barrier between the fire and the wood pole. These wraps help
k
prevent low-burning fires from accessing wood poles, protecting them from
} ! damage or destruction. At Avista, pole wraps are used in areas subject to
routine grassland, sage-shrub, or other low level fires.
Polygons: Between 2017 and 2018 Avista's Vegetation Management planning was changed from circuit
level to polygon level. Polygons contain many circuits.
Protection System: This comprises protective relays,
associated communication systems, voltage and current
sensing devices, station batteries, and DC control
circuitry designed to protect equipment and facilities.
Protective Relays: These devices detect and attempt to
Protective Relay
identify and correct faults. They read measurements such as current, voltage,
and frequency and can be set to recognize when these indicate a problem. For example, if a protective
90

relay senses that a circuit breaker is interrupting the system, it can disconnect it.
Public Safety Power Shutoff
(PSPS): When an electric company
preemptively turn off the power to A* r�
specific areas of the system to
reduce the risk of wildfires and to
9111, P 9
help keep customers and Weather Red Flag Fuel Spark Ignition Fire Behavior
Forecasts Warning ':condition Risk
infrastructure safe. These events
are based on a prediction of risk Public Safety Power Shutoff Deciding Factors
rather than the occurrence of an event.
PSPS Event: Defined as the time from the when the first public safety partner is notified of a planned
public safety de-energization to the final customer being re-energized.
PSPS Weather: Weather that exceeds a utility's risk threshold and creates decisions around initiating a
PSPS in specific areas of the system.
Radial: A transmission or distribution line that does not have a redundant feed — it is a single line
running from the generator to the customer, so if this line is
an �� lost, customers lose service, versus a redundant system that
has another line or lines available to serve load if one line is lost
Power Radial Line Plant (see Looped or Redundant). These are common for low density
rural areas where more complex systems are cost prohibitive.
Recloser: A device that operates similarly to a circuit breaker but is installed on a distribution circuit.
Reclosers are available for both single-phase and three-phase fault interruptions. The main purpose of
a recloser is to sectionalize a portion of a circuit from the rest of the circuit to prevent outages from
spreading. A Viper recloser, which is often used at Avista, provides
automatic overcurrent protection. It detects temporary faults (like a tree
branch falling through a line) and automatically interrupts the power to
isolate the fault, then tries to reclose the circuit to restore the flow of
electricity. These reclosers also provide remote operation and control so
r they can be used to aid in Fire Safety Mode operations.
Red Flag Warning (RFW): Level of wildfire risk based on weather conditions, as declared by the
National Weather Service.
91

Redundant: This is also called a "looped" system means that more OR
than one line or route runs between the generation source and the ReL
or
end customer. If one line is lost, the power is rerouted via another Sy
P 4!
owe
line resulting in a shorter outage or no outage at all. This is a factor in p ant 19
determining whether or not to take a transmission line out of service.
Relative Humidity (RH): Relative humidity is expressed as a percent of the amount of moisture in the
air to the amount of moisture needed to saturate the air. Humidity can either dampen or dry out
potential fuel.
Reliability: Maintaining customer's electric service continuity.
Restoration: When a threat has ended and it is safe to begin making repairs, crews are organized and
dispatched to the site of a power outage.
Risk Based Vegetation Inspections: Risk tree inspections pursuant to our Risk Tree Program.
Risk Tree: A dead, declining, or found to be significantly structurally defective that could imminently
fall into energized facilities.
Right-of-Way(ROW): A right-of-way is the right to come onto a
property owned by another. For a utility, this
allows us to do maintenance and/or tree
trimming work on land that is not our own.
f.r
Right-of-Way Work: ROW work includes re-clearing or reclaiming
the right-of-way with planning and completion of work at the
span (from one pole to the next) level as opposed to spot work 4
planned and completed at the individual tree level. .
Avista transmission right-of-way
Rural: Areas of our service territory with small populations, often restored with low-growing vegetation
having less access to services such as firefighting. This is typically an area with a population of less than
1,000 persons per square mile as determined by the U.S. Census.
Safe Tree Program: This is a partnership with private landowners to remove risk trees on their
property to reduce the chances of their trees contacting powerlines and creating fire potential or loss
of service. This program is offered to customers in high fire threat (typically WUI 2 or 3) areas who
have trees likely to come into contact with our powerlines. At the customer's request the tree is
removed, the debris cleared, and a new low-growing tree is planted in the same place (if they wish to
do so) at no cost to the customer.
92

Sag: For overhead transmission lines, sag is
the difference between the point of I I I F 1,0-spann---op-1
support, being the transmission pole or _ ____ k. ___sag on cold day
tower, and the lowest point on the --------- - --Maximum Sag
Full load,hot day
conductor.
9;L I i I
r
Severe Fire Danger Index (SFDI): This is a
forecastable metric that can help forecast extreme fire conditions based on historical data related to
fire intensity and spread potential. When this data is combined with current wildfires it helps predict
fire intensity, potential resulting damage, and loss of life. This metric helps firefighters and
communities by providing critical information to help improve early warnings and situational
awareness. When we are entering Fire Safety Mode, Avista overlays this information over our service
territory, and when it indicates any "extreme" levels we may declare Fire Safety Mode operations.
Situational Awareness:Tools and programs designed to identify and manage risk, primarily Avista's
Fire Weather Dashboard, WUI Map, weather stations, and wildfire cameras.
Social Impact Team: An internal Avista group that is tasked to work with community-based support
agencies and nonprofit organizations that engage in customer care activities such as the Red Cross,
Aging and Long Term Care of Eastern Washington, the Community Action Partnership, and the Spokane
Tribe Energy Partnership.
Span: The space between adjacent supporting poles or SPAN, SPAN,
structures on a circuit consisting of electric lines and '&%
equipment. #8 A
Spark Ignition Source: Something
that creates a spark that may lead to a fire under certain circumstances, such as a
failed piece of equipment, blown fuse, or conductor that touches dried
�f vegetation on the ground.
Steel Conversion: One of Avista's wildfire mitigation strategies is to replace
wood transmission poles with steel primarily in high canopy areas that are at
an elevated risk of fire as steel is less likely to be damaged and fail when
exposed to fire or other damage risk.
Strike Distance: A term used to describe the distance between a tree and ;
where it may fall into powerlines or other equipment.
Wood to steel conversion on the
Othello-Warden transmission line
93

Substation SCADA/Substation Fire Safety Mode
Automation: Provides automation that allows remote Distops Dispatcher
control and operation of substation equipment to allow it
to respond more quickly if fire conditions indicate elevated
risk. In Avista's Wildfire Plan, fifteen remote substations wide Area
Communications
located in high fire risk areas will be upgraded with r Communication
communications equipment and hardware/software that
Remote
allows them to support fully automated Fire Safety Mode Terminal
operations. Units
Ito Hardware
Sub- Sub Sub-
station Station Statan
Sustained Outage: The IEEE defines a sustained outage as a disruption in power supply lasting more
than five minutes. It is the de-energized condition of a line resulting from a fault or disturbance
following an unsuccessful automatic reclosing sequence and/or unsuccessful manual reclosing
procedure.
Switch: A disconnection point used to interrupt the flow of electricity. Switches can be mounted on
overhead lines, on underground lines, and in substations. Switches mounted overhead and
underground are used as a disconnection point as well as a sectionalizing device. During outages, the
switch can be opened in order to sectionalize the faulted or damaged part of the circuit or reconfigure
power paths to maintain service. Switches mounted in a substation can be used to isolate devices in a
substation, such as a regulator, to protect them in case of fault.
Third-Party Contact: Contact between a piece of electrical equipment and another object, whether
natural (tree branch) or manufactured (vehicle).
Tiers: In Avista's Wildland Urban Interface, the power system is divided into sections based upon the
risk of a fire occurring and having impact. These are called Tiers and include: Tier 0 (Low or no risk),
Tier 1 (Moderate), Tier 2 (Elevated), and Tier 3 (Extreme).
Transmission: Electric facilities that have a voltage of 60 kV or above.
Transmission Corridor: The right-of-way associated with a transmission
line in which the utility has the right to remove vegetation that may
interfere with the line.
Undergrounding: Undergrounding is the replacement of overhead r
distribution powerlines with underground cables. In Avista's current Grid
Hardening efforts, select portions of distribution overhead line will be
converted to underground facilities where feasible and cost justified. Avisto Transmission
corridor
94

Unplanned Outage: Electric outage that occurs unexpectedly with no advance notice from the utility.
Urban: Population centers such as cities and towns, typically having access to firefighting resources.
Includes areas with a population of more than 1,000 persons per square ,
mile as determined by the United States Bureau of the Census.
Vegetation Management, Risk-Based: Under o
Avista s Wildfire Plan, risk tree inspections are 100/
of WUI Tier 2 and 3 polygons, as well as some -
additional rural tiers, and for transmission 100% of
the grid are inspected each year for vegetation ,.
issues.
Vegetation Management, Routine: Trimming, removal, and other
remediations of vegetation used to maintain utility right-of-way and
reduce the risk of outages, ignitions, or other disruption and danger. At
Avista, routine vegetation management is five-year cycle with 20% of
the system completed each year.
Vegetation Risk Index: Risk index indicating the probability of vegetation-caused outages and/or the
potential for ignitions along a particular circuit based on the vegetation species, density, height, growth
rate, etc.
Vulnerable Populations:The State of Washington defines vulnerable populations as people who are
unable to care for themselves, have a developmental disability, or are receiving healthcare services.22
Wedge Connected Stirrups: The traditional hot line tap is attached via a
bolt. Over time this type of connection can come loose, arc and spark,
and melt through the conductor, dropping it to the ground. The wedge
connected stirrup device prevents the hot tap from being directly
connected to the conductor. The stirrup attaches in such a way that if the
connection loosens or if the stirrup melts, the conductor is held in place Wedge Connected
and does not fall to the ground. A wedge connected stirrup is a more Stirrup
permanent connection to the powerline than a hot tap.
Wildfire Impact/Consequence: The effect or outcome of a wildfire, which may be expressed in terms
including, although not limited to, health, safety, reliability, economic and/or environmental damage.
22 Washington State Dept.of Social&Health Services,"Vulnerable Adult,"Vulnerable Adult I DSHS(wa.gov)
95

Wildfire Mitigation Plan:
Except when the context An
suggests otherwise,
"Wildfire Mitigation
Plan" means this Wildfire '©
Mitigation Plan and any
supplements or
amendments thereto. —
Formerly referred to as wildfire Ignition ©Source of Fire Damage ©Urban Conflagration
"Wildfire
r Wildfires can start through both natural and The damage caused by fires comes from If a wildfire reaches a neighborhood of
W i I d f i re Resiliency man-made events.Most wildfire ignitions are radiant heat(flames),embers(burning closely spaced homes,fire can easily spread
man-made,either directly(e.g.,campfires)or chunks of fuel),and smoke.Fires send from house to house.If aided by wind,the
Plan". indirectly(e.g.,utility line spark).Because of embers into the air,which travel downwind entire neighborhood may quickly burn down.
this,wildfires often occur In proximity to and may jump natural barriers,such as rivers
humans-in towns and along road. and road.If they land on dry vegetation,they Smoke Damage
can start new fires.This process of spreading
Wildfire Programs: p Fire Spreadcan be repeated over and over. Fires create large amounts of smoke which
Is then transported by the wind.If the
Fire spreads by wind and through available concentration of smoke is high enough,it
Activities, practices, and fuels.If either goes away,the fire will usually Q Ignition of Structures can result in insurance loss from evacuation
stop spreading. Buildings can be ignited by flames or embers orders(additional living expense),business
which land on the surface of a building or fly closures(business interruption),and
strategies that are only into vents and windows. contents loss from contamination.Smoke
can cause damage far beyond the fire
necessitated by wildfire perimeter during a wildfire event.
risk beyond that required by minimum reliability and/or safety requirements. Such programs are not
indicated or in common use in areas where wildfire risk is minimal (e.g., territory with no vegetation or
fuel) or under conditions where wildfires are unlikely to ignite or spread (e.g., when rain is falling).
Wildfire Risk Reduction:The average percentage difference between the current state of risk and
future state risk levels as wildfire measures are implemented.
Wildland Urban Interface: Or "WUI", is the zone of transition between wilderness (unoccupied land)
and land developed by human activity; basically, where the natural environment (typically forested
areas) meets the built environment.
Wire Down: Instance where an electric transmission or distribution conductor is broken and falls from
its intended position to rest on the ground or on a foreign object. 1
Wood Pole Wraps: See "Pole Wrap"
�7111
96

I
Wi I d f'10 r e
M 'W1.4
zi • a tio •
Plan
'AAAAA,1026
Appendix A: '
Commission Orders
Recommendations
w.•
7,

Appendix A: Commission Orders & Recommendations
Idaho Requirements Crosswalk
Requirement/
WMP Reference Details/ Notes
Guideline
Executive Summary (p.7)
WUI Risk Area (p.9)
Resiliency Program (p.10)
Plan Development & Situational Awareness (p.11)
Cost/Risk Balance Grid Hardening (p.19) Plan must reflect utility
size/complexity and fire risk;
WSCA 61-1803 (3) Vegetation Management (p.29)
balance cost vs. risk reduction.
Emergency Response (p.41)
PSPS (p.47, Appendix F)
Preparing for Wildfire (p.57)
WUI Risk Area (p.9)
Identifying High-Risk Fire Weather Dashboard (p.11) Risk assessment/model, map of
Areas PSPS (p.47, Appendix F) risk areas, annual updates.
(3)(a) Vegetation Management (p.29)
Situational Awareness (p.11)
Grid Hardening (p.19)
Vegetation Management (p.29)
Technology, inspections,
Emergency Response (p.41)
vegetation management,
Preventative Actions & Preventing and Mitigating
Programs Vegetation Fires while operational practices, community
education, system hardening,
(3)(b) performing Avista Work
workforce preparedness, pilot
(Appendix D)
Public Outreach (p.66) programs.
Communication Plan (Appendix
F)
PSPS (p.47)
Preparing for Wildfire (p.57) Customer communication,
Community Outreach & Outreach (p.66) education, notification protocols,
Public Awareness Lessons Learned (p.119) methods (mail, flyers, emails, calls,
(3)(c) Communication Plan (Appendix
texts, website).F)
PSPS Plan (Appendix F)
1

Requirement/ WMP Reference Details/ Notes
Guideline
Line Design Methods Grid Hardening (p.19) Methods for new/planned lines,
(3)(e) Lessons Learned (p.73) cost evaluation, project selection,
3rd Party Cost-Benefit Analysis covered conductor, non-wooden
for Undergrounding (Appendix cross arms, flexible infrastructure.
B)
Weather Monitoring Situational Awareness (p.11) Systems/tools for monitoring,
3 f Emergency
Response 41 integration into operations,
PSPS
( )( ) y p (p ) coordination with other utilities.
Grid Hardening (p.19)
Inspection standards/schedules,
Standards, Procedures, Vegetation Management (p.29)
defect correction, measurable
Schedules(3)(g) & (i) Lessons Learned (p.73)
targets/goals.
Metrics/Targets (Appendix B)
Emergency Response (p.41)
Conditions, criteria, operational
De-energization PSPS (p.47)
Protocols Preparing for Wildfire (p.57) protocols, coordination with
emergency managers, community
(3)(g)(ii) Outreach (p.66)
PSPS Plan (Appendix F) impact mitigation.
Vegetation Vegetation Management (p.29) Standards, procedures, schedules,
Management enhancements, agency
Budgets/Targets (Appendix B)
(3)(g)(iii) recommendations, measurable
targets/goals.
2

Montana Requirements Crosswalk
Requirement/Guideline WMP Reference
WUI Risk Areas (p.9)
Areas with Heightened Wildfire Risk (2)(a) Fire Weather Dashboard (p.11)
PSPS (p.47)
Vegetation Management (p.29)
Grid Hardening (p.19)
Inspection, Maintenance, Emergency Response (p.41)
Operation Strategies (2)(b) Lessons Learned (p.73)
PSPS Plan (Appendix F)
Vegetation Management
Vegetation Management (p.29)
Strategies (2)(c)
Facility Modifications/Upgrades (2)(d) Grid Hardening (p.19)
Emergency Response (p.41)
Situational Awareness (p.11)
De-energization Strategies/ Emergency Response (p.41)
Methods (2)(e) PSPS (p.47)
Preparing for Wildfire (p.57)
Lessons Learned (p.73)
PSPS Plan (Appendix F)
Situational Awareness (p.11)
Restoration Methods Emergency Response (p.41)
After De-energization (2)(f) PSPS (p.47)
Lessons Learned (p.73)
PSPS Plan (Appendix F)
Estimated Incremental
Budgets/Targets (Appendix B)
Costs (2)(g)
PSPS (p.47)
Community Outreach/ Preparing for Wildfire (p.57)
Public Awareness (2)(h) Outreach (p.66)
Lessons Learned (p.73)
PSPS Plan (Appendix F)
Participation in State/ Vegetation Management (p.29)
Local Plans (2)(i) Outreach & Engagement (p.66)
3

/IIw _
�►�ii/ISTA��
Wiol d f'0 r e
Miatiagation
Plan
2026
t
Appendix
Budget & Targets
WIW
Ad
11-R-4-M-
. S
�1

Idaho Wildfire Mitigation Plan and Targets
Grid Hardening
Category 2026 2027 2028 2029 2030
CapEz
Distribution Grid Hardening
Budget $300,000 $1,700,000 $9,900,000 $24,200,000 $17,500,000
High Risk Mitigated Miles Planning&Engineering Planning&Engineering 5 Miles 16 Miles 14 Miles
Grid Hardening Wood Pole Mgmt
Budget $1,600,000 $1,600,000 $1,600,000 $1,600,000
Poles refreshed in High Risk Areas 1,100 Poles Refreshed 1,100 Poles Refreshed 1,100 Poles Refreshed 1,100 Poles Refreshed
Transmission Grid Hardening
Budget $3,500,000 $3,500,000 $3,500,000 $1,400,000 $1,400,000
High Risk Mitigated Miles 7.1 Miles 3.6 Miles 3.6 Miles TBD Miles TBD Miles
Transmission Remediation
Budget $400,000 $400,000 $400,000 $400,000 $400,000
inspection and Equipment Replacement Actual#poles/equip Actual#poles/equip Actual#poles/equip Actual#poles/equip Actual#poles/equip
Operations and Emergency Response
Category 2026 2027 2028 2029 2030
CapEx
Distribution Automation
Budget $1,480,000 $800,000 $800,000 $800,000 $800,000
Line Segmentation 10 Midlines 5 Midlines 5 Midlines 5 Midlines 5 Midlines
Partner Portals
Budget $200,000 $600,000
Mobile and Web App Phase 1 Partner App Complete Phase 2 Customer App Complete
Substation Automation
Budget $1,780,000 $1,800,000 $1,400,000 $1,400,000 $1,400,000
Substation Breakers Updated 7 Breakers 2 Breakers 5 Breakers 5 Breakers 5 Breakers
1

Situational Awareness
Category 2026 2027 2028 2029 2030
CapEx
Wildfire Risk Assessment
Risk Modeling Project Complete Enhancements
Budget $400,000 $800,000
Weather Stations
Neather Station Installations 40 installed 40 installed 40 installed
Budget $1,000,000 $1,000,000 $1,000,000
Al Detection Cameras
Camera Installations 10 Cameras 4 Cameras 4 Cameras 4 Cameras 4 Cameras
Budget $2,500,000 $1,000,000 $1,000,000 $1,000,000 $1,000,000
Aerial Inspection and Apparatus
Budget $500,000 $500,000 $500,000 $500,OD0 $500,000
Vegetation Management
Category 2026 2027 2028 2029 2030
O&M
Distribution Satellite
Budget $43,000 $43,000 $43,000 $43,000 $43,000
Fuel Reduction Partnership
Budget $154,000 $154,000 $154,000 $154,000 $154,000
Treated Acres 70 acres 70 acres 70 acres 70 acres 70 acres
Risk Tree Reduction
Actual#of Risk Trees Mitigated #of Risk Trees #of Risk Trees #of Risk Trees #of Risk Trees #of Risk Trees
Budget $5,600,000 $5,800,000 $5,900,000 $6,170,000 $6,170,000
Miles Inspected 2,140 Miles 2,140 Miles 2,140 Miles 2,140 Miles 2,140 Miles
Safe Tree Program
Budget $627,000 $640,000 $666,000 $692,000 $718,000
Trees Mitigated by Customers #of Trees #of Trees #of Trees #of Trees #of Trees
Transmission HDAR
Budget $360,000 $360,000 $360,000 $360,000 $360,000
2

Washington Wildfire Mitigation Plan and Targets
Grid Hardening
Program 2026 2027 2028 2029 2030
Grid Hardening
CapEx
Distribution Grid Hardening
Budget $23,500,000 $28,100,000 $24,800,000 $19,900,000 $26,700,000
High Risk Mitigated Miles 42 Miles 17 Miles 25 Miles 20 Miles 17 Miles
Grid Hardening Wood Pole Mgmt
Budget $3,000,000 $2,400,000 $2,400,0D0 $2,400,0D0 $2,400,000
Poles refreshed in High Risk Areas 2,400 Poles Refreshed 1,700 Poles Refreshed 1,700 Poles Refreshed 1,700 Poles Refreshed 1,700 Poles Refreshed
Transmission Grid Hardening
Budget $2,100,000 $2,100,000
High Risk Mitigated Miles TBD Miles TBD Miles
Transmission Remediation
Budget $600,000 $600,000 $600,000 $600,000 $600,000
Inspection and Equipment Replacement Actual#poles/equip Actual#poles/equip Actual#poles/equip Actual#poles/equip Actual#poles/equip
Operations and Emergency Response
Category 2026 2027 2028 2029 2030
CapEx
Distribution Automation
Budget $2,220,000 $1,200,000 $1,200,000 $1,200,000 $1,200,000
Line Segmentation 3 Midlines 8 Midlines 8 Midlines 8 Midlines 8 Midlines
Partner Portals
Budget $300,000 $900,000
Mobile and Web App Phase 1 Partner App Complete Phase 2 Customer App Complete
Substation Automation
Budget $910,000 $630,000 $600,000 $600,000 $600,000
Substation Breakers Updated 2 Breakers 2 Breakers 2 Breakers 2 Breakers 2 Breakers
3

Situational Awareness
Category 2026 2027 2028 2029 2030
CapEx
Aerial Inspection and Apparatus
Budget $300,000 $500,000 $500,000 $500,000 $500,000
Al Detection Cameras
Budget $1,500,000 $1,500,000 $1,500,000 $1,500,000
Camera Installations 6 Cameras 6 Cameras 6 Cameras 6 Cameras
Weather Stations
Budget $1,500,000 $1,500,000 $1,500,000
Weather Station Installations 60 installed 60 installed 60 installed
Wildfire Risk Assessment
Budget $600,000 $1,200,000
Risk Modeling Project Complete Enhancements
Vegetation Management
Category 2026 1 2027 2028 2029 2030
O&M
Distribution Satellite
Budget $64,000 $64,000 $64,000 $64,000 $64,000
Fuel Reduction Partnership
Budget $146,000 $146,000 $146,000 $146,000 $146,000
Treated Acres 145 acres 145 acres 145 acres 145 acres 145 acres
Risk Tree Reduction
Actual#of Risk Trees Mitigated #of Risk Trees #of Risk Trees #of Risk Trees #of Risk Trees #of Risk Trees
Budget $8,400,000 $8,700,000 $8,900,000 $9,242,000 $9,242,000
Miles inspected 4,234 Miles 4,234 Miles 4,234 Miles 4,234 Miles 4,234 Miles
Safe Tree Program
Budget $941,000 $960,000 $999,000 $1,038,000 $1,077,000
Trees Mitigated by Customers #of Trees #of Trees #of Trees #of Trees #of Trees
Transmission UDAR
Budget $540,000 $540,000 $540,000 $540,000 $540,000
4

/IIw _
Wildfire
Ma aga ion
plan
2026
Appendix
Pa rty
Undergrounding
ProjectM
1

E lx
ponent'
Cost-Benefit Analysis for
Avista Undergrounding
Projects

Exponent'
Cost-Benefit Analysis for Avista Undergrounding Projects
Prepared For:
Heather Webster
Manager Asset Maintenance Program Delivery
Avista Corp.
Spokane, WA 99202
Prepared By:
�� omf��
Ezra Jampole, Ph.D., P.E. Kristen Hollingsworth, Ph.D.
Exponent, Inc.
149 Commonwealth Drive
Menlo Park, CA 94025
October 30, 2024
© Exponent, Inc.
Page 11 2407043.000-9196
tplver1.0

October 30, 2024
Contents
Page
List of Figures v
List of Tables vi
Limitations vii
Executive Summary 1
Project Background 3
Cost-Benefit Analysis Components 4
Methodologies 5
Outages Customer Impacts Analysis 5
Outage Direct Costs 21
Operations and Maintenance 24
Vegetation Management 24
Other O&M 26
Wildfire Losses 26
Wood Poles Failure Rates 30
Overview of Methodology 30
Hazard Curves 32
Fragility Curves 34
Calculated Wood Pole Failure Rates 41
Calculating Benefit-Cost Ratios 41
Costs of Undergrounding 43
Cost-Benefit Analysis Results 44
Recommendations for Future Study 49
Rationale for Incorporating Scenario Risk Analysis 51
Fat-tailed distributions and uncertainty 51
E,,, TM
x
Page Ill 2407043.000-9196 ✓AV.

October 30, 2024
Scenario risk analysis as a complementary method 53
Application to Avista's Proposed Undergrounding Projects 53
ExTM
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October 30, 2024
List of Figures
Page
Figure 1. Total customer count(top) and total customer outage hours (bottom)for each outage
reason and subreason combination. 6
Figure 2. Total customer count(top) and total customer outage hours (bottom) for each feeder
where the feeder names are shown for visual context only and not intended to be
legible. 7
Figure 3. Distribution of total feeder lengths and proposed undergrounded feeder lengths for
370 and 195 feeders,respectively. 8
Figure 4. Distribution of total customers per feeder for 384 feeders. 8
Figure 5. Distribution of mitigated interruption costs per year for 195 feeders with proposed
undergrounding. 21
Figure 6. Distribution of mitigated direct costs per year for 195 feeders with proposed
undergrounding. 24
Figure 7. Histogram of vegetation management costs per year per mile for each feeder. 25
Figure 8. Example Hexes from Avista's Consequence Analysis. 27
Figure 9. Proportion of wildfires and acres burned in California caused by electric power from
2016 to 2020. 28
Figure 10. Sample hazard curve (left)and fragility curve(right). 32
Figure 11. Contours from ASCE Hazard Tool for 300-year wind speed. 33
Figure 12. Contours from ASCE Hazard Tool for 700-year wind speed. 33
Figure 13. Example wind speed hazard curve and underlying MRI data. 34
Figure 14. Loss of strength and increased dispersion as wood poles age(from EPRI, 1986). 35
Figure 15. Histogram of wood pole ages for each shell rot condition code. 38
Figure 16. Estimate of Remaining Strength as a function of age;used in the absence of shell rot
condition code or explicit measurement of remaining strength. 39
Figure 17. Example relationship between pole age and fragility curve dispersion parameter,/3. 40
Figure 18. Histogram of estimated wood pole annual failure rates. 41
Figure 19. Distribution of the estimated cost to underground for 177 feeders. 43
Ex TM
Page V 2407043.000-9196

October 30, 2024
List of Tables
Page
Table 1. System-Wide Parameters Calculated Using All Available Outages 11
Table 2. Feeder Specific Outage Rates for Feeders with Proposed Undergrounding 12
Table 3. Proportion Mitigation Effectiveness due to Undergrounding 16
Table 4. Example Outage Benefit Calculation for a Feeder 17
Table 5. Outage Benefit Analysis Results for Feeders with Proposed Undergrounding 18
Table 6. Example Mitigated Annual Direct Cost Calculation for a Feeder 22
Table 7. Assumed remaining strength for different shell rot conditions. 37
Table 8. Mapping of Age to Remaining Strength 38
Table 9. Cost-Benefit Analysis Results by Feeder 44
E,,, TM
X
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October 30, 2024
Limitations
The study presented in this report is intended for use by Avista Corp. to assist with their
decisions regarding underground sections of their distribution feeders. Proper application of this
report requires recognition and understanding of the limitations of both the scope and
methodology of the study.
The risk assessment methodology forming the basis of the results presented in this report is
based on mathematical and statistical modeling of physical systems and processes as well as data
from third parties. Given the nature of these evaluations, significant uncertainties are associated
with the various hazard and loss computations, some of which are accounted for in the
methodology, while other uncertainties such as as-built construction details, modifications,
current conditions, material characteristics, among others cannot be explicitly incorporated into
the analyses. These uncertainties are inherent in the methodology and subsequently in the
generated hazard and loss results. These results are not facts or predictions of the loss that may
occur as a result of future events or any specific event; as such, the actual losses may be
materially different from those presented in this study. Furthermore, the assumptions adopted in
determining these loss estimates do not constitute the exclusive set of reasonable assumptions,
and the use of a different set of assumptions or methodology could produce materially different
results.
Ex TM
Page V 11 2407043.000-9196

Executive Summary
This study contains a cost-benefit analysis ("CBA") of selected portions of feeders on Avista's
overhead to inform potential distribution undergrounding projects on around 190 feeders in
Washington and Idaho. The purpose of the undergrounding projects is to improve reliability and
reduce the likelihood of an Avista-caused ignition and consequent wildfire. The analysis
contained herein considers three key components that are relevant to utilities: safety, reliability,
and direct financial considerations. Safety considers the economic value associated with loss of
life and injuries; reliability considers the financial impact of service outages; and direct financial
considers includes directs costs of implementing undergrounding projects, direct costs from
outages, and operations and maintenance ("O&M") costs.
Fundamentally, the CBA calculates benefit-cost ratios ("BCR") for each potential
undergrounding project. The BCR is the ratio of the benefits of undergrounding, i.e., the sum of
the reduced costs over the expected life of the project, assumed to be 76.5 years, divided by the
costs associated with the undergrounding project. Ultimately, all benefits and costs are translated
to a monetary figure to be included in the BCR calculation. A discount rate of 6.89%was used,
to be consistent with other Avista investment decisions. A BCR greater than 1 indicates that the
benefits exceed the costs, suggesting that the undergrounding project on that feeder is financially
advisable. Conversely, a BCR less than 1 indicates that the costs exceed the benefits, suggesting
that the undergrounding project on that feeder is not financially advisable.
The benefits are calculated using a variety of methodologies:
• Reliability benefits are calculated by estimating rates of outages with and without an
undergrounding project. Analysis of historical outages from around 40 mechanisms was
undertaken, with statistical checks for whether each mechanism's outage rate (outages
per mile per year) is feeder-specific, or if a general rate is applicable to the mechanism.
The effectiveness of the undergrounding mitigation was estimated based on subject
matter expertise and engineering judgement. Combined initial outage rates with
mitigation effectiveness and customer counts, the change in expected number of outages
is computed. This is translated to a dollar value using Avista-specific customer
interruption costs for Washington and Idaho.
• Changes in direct costs are estimated based on historical costs of outages and the change
in outage rates.
• Changes in O&M costs are calculated based on historical Avista data on maintenance
costs for overhead and underground feeders and the length of each feeder that is intended
to be undergrounded.
• Reductions in costs associated with Avista-caused wildfire are calculated by apportioning
expected annual losses from FEMA's National Risk Index to utility-caused fires, and to
specific feeders based on the relative risk and estimated wood pole and tree fall failure
rates along the feeder. Wood pole failure rates were calculated using fragility curves,
Page 1 2407043.000-9196 t x TM

October 30, 2024
relating wind speed to probability of failure, and hazard curves, relating frequency of
exceedance to wind speed, with reference to remaining strength and pole condition from
test and treat data.
• Costs associated with undergrounding projects were provided by Avista and consider
fixed costs associated with project labor, civil construction costs, truck and lateral build
costs, distribution automation costs, and service transfer and overhead wreckout costs.
Calculated BCRs range from values of 0.06 to 11, indicating that there is varying financial utility
in performing specific undergrounding projects. While some of the proposed undergrounding
projects have BCR values less than 1, components of the analysis that consider contributions to
the "benefits" consider both the consequence and the frequency of the consequence. In
particular, the wildfire frequency, which is typically low, is considered in FEMA's calculation of
wildfire losses, which informed this study. However, a catastrophic wildfire would have drastic
consequences far exceeding the cost of any undergrounding projects, if it were to occur,
potentially causing irreparable harm to Avista and its customers. It is thus worth considering the
severity of the consequences, independent of the frequency of their occurrence, as part of the
decision-making process for undergrounding. Scenario-based risk analysis, which considers only
consequences and no probability, is a valid academic exercise for making decisions on low-
probability high-consequence hazard mitigation.
Several recommendations for further study were identified through the course of this analysis:
• Wildfire consequence modeling that explicitly estimates structures burned, acres burned,
and lives lost, as well as estimates of ignition probabilities along specific feeders, would
improve the wildfire cost portion of the model;
• Data collection of remaining pole strength and connectivity between poles and
conductors would enable more sophisticated fragility-based analysis of poles, which
informs the wildfire model.
• The current analysis only considers undergrounding projects specifically identified by
Avista, however, optimization strategies could be used to identify projects with high
BCRs;
• Other contributors to costs and benefits, such as aesthetic benefits (home values),
construction-associated injuries and fatalities, and economic impact on ratepayers could
be considered.
Page 2 2407043.000-9196 t x TM

October 30, 2024
Project Background
Avista is currently preparing its Wildfire Resiliency Plan("WRP")update for calendar year
2024. In conjunction with that plan, Avista is considering strategically undergrounding sections
of their distribution system to reduce wildfire risk. Exponent has been asked to perform a cost-
benefit analysis for undergrounding projects being considered on a feeder-by-feeder basis.
Exponent has performed a cost-benefit analysis of undergrounding projects on each selected
feeder, considering costs (estimated by Avista), and the benefits derived from the expected
reduction in consequences considering life-safety, economic loss,protection of property, and
customer outage duration. Quantitative risk analysis techniques have been used throughout the
assessment. The analysis has produced benefit-cost ratios for the projects proposed on each
feeder, considering the estimated project design life.
Page 3 2407043.000-9196 t x TM

October 30, 2024
Cost-Benefit Analysis Components
Cost-benefit analyses for utility projects typically consider three key components:
1. Safety: loss of life and injuries to people and property associated with the
projects, e.g., stemming from changes in wildfire risk.
2. Reliability: customers impacted by the project in terms of outage hours.
3. Financial: direct costs associated with the project, including both the cost of
executing the project and costs or benefits associated with maintenance.
Exponent has considered these three key components through a variety of analyses.
Safety:
- Loss of life and injuries to people, land, and property is considered within the
analysis of reductions in expected wildfire event rates when undergrounding
projects are implemented.
Reliability:
- Analysis of outage data including outage rates, outage durations, and customers
impacted on each feeder, combined with consideration of how undergrounding
affects the likelihood of different types of outages is used to determine the
expected change in customer-outage hours for each feeder with proposed
undergrounding segments.
Financial:
- The direct costs of implementing each undergrounding project was calculated by
Avista for each feeder. Exponent understands that these costs include restoration
and environmental considerations.
- The change in direct costs associated with outages is estimated, with
consideration to how undergrounding affects the likelihood of different types of
outages.
- The change in operations and maintenance ("O&M") costs are estimated based on
Avista's O&M historical costs for the overhead and underground components of
their system.
Page 4 2407043.000-9196 Fx TM

October 30, 2024
Methodologies
Outages Customer Impacts Analysis
The purpose of this analysis is to determine the benefit, in terms of dollars, due to the reduction
in frequency and duration of outages when select feeder sections are undergrounded.
To perform the outage benefit analysis, Avista provided datasets for outages, feeder lengths, and
total customers per feeder. The outage dataset contains reported outages by feeder between
January 2018 and June 2024, and categorized the outages into 38 reason and subreason
combinations. For each outage, the outage dataset includes the outage duration (hours) and the
number of customers impacted. Figure 1 shows the total customer count and total outage
duration by outage reason and subreason combination. Weather and its subreasons has the
highest total customer count and total outage duration. Figure 2 shows the total customer count
and total customer outage hours by feeder. Some feeders have more impacted customers, while
other feeders have more total outage hours. The feeder length dataset includes total overhead
(OH) feeder lengths and proposed undergrounded feeder lengths. Figure 3 shows the distribution
of the total OH feeder lengths and proposed undergrounded feeder lengths. The overhead system
is comprised of primarily shorter feeders (<25 miles) and the proposed undergrounded sections
are typically less than 10 miles. Figure 4 shows the distribution of total customers per feeder,
ranging from a few customers to around 3,500 customers.
Page 5 2407043.000-9196 t x TM

October 30, 2024
600
500
o
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a 300
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Co
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Q.4J4J\�dJ4J\4J\Q Q,a �C3 Q. J\Q J\Q�O�Q\, J�O
Outage Reason: Subreason
Figure 1. Total customer count (top) and total customer outage hours (bottom)for each
outage reason and subreason combination.
TM
Page 6 2407043.000-9196 �/�'

October 30, 2024
80
0 —60
U N
`m C:
Co
0 5 40
fn 0
7 aL+
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Fa 20
H
0
500
y
0
x 400
0
m
300
O N
a w 200
0
U 100
m
F
0
Feeder Name
Figure 2. Total customer count (top) and total customer outage hours (bottom) for each
feeder where the feeder names are shown for visual context only and not
intended to be legible.
TM
Page 7 2407043.000-9196 t,

October 30, 2024
90
OTotal Feeder Length
80 0 Proposed Undergrounded Feeder Length
70
;n 60
50
0
�5 40
E
Z 30
20
10
0
0 50 100 150 200
Feeder Length (mi)
Figure 3. Distribution of total feeder lengths and proposed
undergrounded feeder lengths for 370 and 195
feeders, respectively.
60
50
E 40
am
-a
LL
am
0 30
s
E
Z 20
10
0
0 500 1000 1500 2000 2500 3000 3500 4000
Total Customers per Feeder
Figure 4. Distribution of total customers per feeder for 384
feeders.
TM
Page 8 2407043.000-9196 t,

October 30, 2024
The provided datasets were used to determine the benefit associated with reduced customer
hours interrupted due to undergrounding projects on each feeder, which we refer to as the
mitigated cost. The procedure to determine the mitigated cost is as follows:
l. The outage rate is the frequency of service interruptions per unit feeder length. The
outage rate for an outage reason and subreason combination could be specific to the
feeder or be consistent system-wide. For example, a feeder may be located in an area
with more squirrels, which would increase the frequency of ANIMAL: Squirrel outages
for that feeder relative to other feeders. Conversely, a certain EQUIPMENT OH related
outage may equally affect all feeders because the equipment is subject to random failures
and relatively unaffected by age or environmental factors. For each outage reason and
subreason combination (o), the feeder specific or system-wide outage rate (R°)
(outages/yr./mi.) is determined according to:
outages°
_ t x ELF
system-wide
R° — outages°,F
feeder specific
txLF
Where outages°,F is the number of outages on a specific feeder (F) for an outage reason
and subreason combination, outages° is the number of outages for an outage reason and
subreason combination, t is the time (yrs.) over which the outages occurred, LF is the
length of feeder, and Z LF is the total length of all considered feeders. The system-wide
and feeder specific outage rates are shown in Table 1 and Table 2, respectively.
2. For an outage reason and subreason combination, statistical significance checks were
performed to determine whether outage rates for each subreason are likely to be feeder-
specific or if it is more appropriate to apply the system-wide outage rate. The designation
for whether the outage rate is feeder-specific or uses a system-wide rate for each outage
reason and subreason combination is provided in Table 1.
3. It is assumed that the proportion of customers impacted by an outage is specific to the
outage reason and subreason combination,but not feeder-specific. For each outage
reason and subreason combination (o), the average proportion of customers impacted by
an outage (CI°) is determined as follows:
n
1 Custlmpi,F
_
CIO n I CustTotF
Where n is the number of outages for an outage reason and subreason combination,
Custlmpi,F is the customers on feeder F impacted by outage instance i, and CustTotF is
the total number of customers on feeder F.
, TM
Page 9 2407043.000-9196 t

October 30, 2024
4. It is assumed that the duration of outages is specific to the outage reason and subreason
combination,but not feeder-specific. For each outage reason and subreason combination
(o), the average duration of an outage (Do) is determined as follows:
n
1
Do = n Di
i=1
Where n is the number of outages for an outage reason and subreason combination and
Di is the duration (hours) of outage instance L
5. The annual customer outage-hours per feeder(ACOHF) is determined using parameters
determined from the outage dataset as follows:
°total
ACOHF = Y, Ro LF CustTotF CIO Do
0=1
Where ot0tai is the total number of outage reason and subreason combinations. The
calculated parameters are shown in Table 1, Table 2, and Table 5.
6. The mitigated annual customer outage-hours is the reduction in customer outage hours if
the proposed undergrounding projects are completed. The mitigated annual customer
outage-hours per feeder(Mitigated ACOHF) is determined using parameters related to
undergrounding according to:
0total
Mitgated ACOHF = Y, ACOHF UGF MEo
0=1
Where °total is the number of outage reason and subreason combinations, UGF is the
proportion of the feeder that is proposed to be undergrounded (see Table 5), and MEo is
the proportion mitigation effectiveness of undergrounding to reduce outages for the
outage reason and subreason combination (see Table 3). An example of the calculation of
Mitigated ACOHF for a feeder is shown in Table 4.
7. For each feeder, the interruption cost per customer outage-hour, ClCostF, was
determined using the state specific interruption cost and the proportion of poles on the
feeder located in that state. Avista provided the interruption costs per customer outage-
hour of$94.62/hr. and $127.37/hr. for Washington and Idaho, respectively. For a limited
number of poles located in Montana, the Idaho interruption costs per customer outage-
hour were used.
8. The mitigated annual interruption cost is the reduction in annual costs if the proposed
undergrounding projects are completed and is calculated as follows:
Mitgated AICostF = Mitgated ACOHF x ClCostF
TM
Page 10 2407043.000-9196 ��

October 30, 2024
An example of the calculation for one feeder is shown in Table 4.
The feeder-specific annual reduction in costs associated with customer interruptions is shown in
Table 5 and Figure 5. Table 5 shows the results for 195 feeders with proposed undergrounding,
and Figure 7 shows a histogram of the mitigated annual interruption costs provided in Table 5.
Table 1. System-Wide Parameters Calculated Using All Available Outages
Outage Reason: Feeder Specific or System-Wide R. Do (hrs.) Clo
Subreason System-Wide Outage Rate? (outages/yr./mi.)
ANIMAL: Bird Feeder Specific N/A 1.69 0.037
ANIMAL:Other System-Wide 0.00327 1.88 0.053
ANIMAL: Protected System-Wide 0.00018 1.60 0.073
ANIMAL:Squirrel Feeder Specific N/A 1.46 0.015
COMPANY:Other System-Wide 0.01059 1.39 0.150
EQUIPMENT OH: Feeder Specific N/A 2.05 0.049
Arrester
EQUIPMENT OH: System-Wide 0.00018 2.38 0.121
Capacitor
EQUIPMENT OH: System-Wide 0.01047 3.24 0.149
Conductor-Pri
EQUIPMENT OH: Feeder Specific N/A 2.01 0.005
Conductor-Sec
EQUIPMENT OH: Feeder Specific N/A 2.61 0.081
Connector-Pri
EQUIPMENT OH: System-Wide 0.00828 1.82 0.004
Connector-Sec
EQUIPMENT OH: System-Wide 0.00164 3.15 0.093
Crossarm-rotten
EQUIPMENT OH: Feeder Specific N/A 2.29 0.032
Cutout/Fuse
EQUIPMENT OH: System-Wide 0.00247 2.92 0.226
Insulator
EQUIPMENT OH: System-Wide 0.00142 2.86 0.102
Insulator Pin
EQUIPMENT OH:Other System-Wide 0.00373 2.30 0.078
EQUIPMENT OH: Pole- System-Wide 0.00112 4.59 0.020
rotten
EQUIPMENT OH: System-Wide 0.00030 2.38 0.523
Recloser
EQUIPMENT OH: System-Wide 0.00020 2.60 0.339
Regulator
EQUIPMENT OH: System-Wide 0.00040 1.40 0.417
Switch/Disconnect
EQUIPMENT OH: Feeder Specific N/A 3.88 0.025
Transformer-OH
EQUIPMENT OH:Wildlife System-Wide 0.00002 4.39 0.009
Guard
MISCELLANEOUS:SEE System-Wide 0.00114 2.38 0.004
REMARKS
POLE FIRE: Pole Fire System-Wide 0.00890 4.47 0.230
PUBLIC:Car Hit Pole Feeder Specific N/A 3.03 0.247
PUBLIC: Fire Feeder Specific N/A 1.54 0.013
PUBLIC:Other Feeder Specific N/A 1.82 0.040
PUBLIC:Tree System-Wide 0.00403 2.87 0.074
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October 30, 2024
Outage Reason: Feeder Specific or System-Wide R. Do (hrs.) Cio
Subreason System-Wide Outage Rate? (outages/yr./mi.)
TREE:Service Feeder Specific N/A 2.05 0.003
TREE:Tree Fell Feeder Specific N/A 3.15 0.099
TREE:Tree Growth Feeder Specific N/A 1.93 0.032
TREE:Weather Feeder Specific N/A 5.63 0.071
WEATHER:Heat System-Wide 0.00004 7.96 0.002
WEATHER:Lightning Feeder Specific N/A 3.99 0.070
WEATHER:Snow/Ice Feeder Specific N/A 10.29 0.063
WEATHER:Wildfire System-Wide 0.00030 9.57 0.497
WEATHER:Wind Feeder Specific N/A 17.22 0.074
UNDETERMINED: Feeder Specific N/A 2.10 0.098
Undetermined
Table 2. Feeder Specific Outage Rates for Feeders with Proposed Undergrounding
Feeder Specific Ro (outages/yr./mi.)
ANIMAL EQUIPMENT OH PUBLIC TREE WEATHER UNDETER-
MINED
U =
- O
C0 (L
y L �
U LL d O N f=
Feeder a o r o C
Name* a` C) C) L U LL o U) � U m U) D
9CE12F4 0.018 0.036 0 0.036 0 0 0 0.054 0.073 0.036 0.018 0.018 0 0 0.018 0.054 0.109 0.073
9CE12F6 0.018 0.018 0.036 0.009 0 0 0 0.0180.0180 0.009 0.118 0.018 0 0 0.236 0.517 0.018
AIR12F1 0.033 0.047 0.014 0 0.003 0.011 0.011 0.017 0.003 0.008 0 0 0.003 0 0.019 0.006 0.053 0.022
AIR12F2 0.045 0 0.011 0.011 0.011 0.011 0 0.123 0.034 0.011 0 0 0 0 0.011 0.034 0.056 0.034
AIR12F3 0.110 0 0 0 0 0.027 0 0 0.055 0.027 0 0 0 0 0.027 0.027 0.055 0.055
APW112 0.023 0.058 0.023 0.035 0.023 0.012 0.012 0.081 0.058 0.012 0.035 0.070 0.012 0.012 0.058 0.023 0.336 0.104
APW113 0.026 0.026 0.013 0 0 0.026 0.013 0.013 0 0 0 0.052 0.039 0.026 0.026 0.091 0.389 0.065
ARD12F2 0.044 0.019 0.003 0.005 0.022 0.011 0.003 0.008 0.022 0.005 0 0.047 0.003 0.005 0.069 0.077 0.069 0.159
AVD151 0.014 0.054 0.020 0 0 0.020 0.014 0.020 0.034 0.014 0 0.047 0.007 0.007 0.014 0.054 0.440 0.027
AVD152 0.040 0 0.027 0 0 0.027 0.013 0.053 0.053 0 0.027 0.013 0.053 0 0 0.080 0.306 0.067
BEA12F2 0.056 0.152 0.008 0.032 0.016 0.024 0.016 0.064 0.032 0.040 0.024 0.040 0.032 0.024 0.008 0.112 0.176 0.080
BEA13T09 NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
BIG411 0.032 0.011 0 0.011 0.021 0 0.011 0 0.021 0 0.011 0.159 0.011 0.021 0 0.042 0.127 0.117
BIG412 0 0 0 0.023 0 0 0.023 0 0.047 0.023 0 0.094 0 0.023 0 0.070 0.329 0.023
BIG413 0 0 0 0 0 0 0 0 0 0 0 0.183 0 0.061 0 0 0.122 0.061
BKR12F1 0.090 0.090 0 0 0 0 0 0 0.090 0.030 0 0.030 0.030 0 0 0 0.179 0.060
BKR12F2 0.110 0.028 0.055 0 0 0 0.028 0.055 0.083 0.028 0 0.055 0 0.028 0 0 0 0.028
BKR12F3 0.080 0.080 0 0 0.013 0.013 0 0 0.027 0 0.027 0.013 0 0.013 0.013 0.027 0.094 0.027
BLA311 0 0.019 0.010 0 0 0.024 0.014 0.014 0.005 0 0 0.062 0 0.033 0.019 0.024 0.163 0.053
BLD12F4 0.130 0.142 0.012 0.036 0 0.012 0.047 0.047 0.036 0.012 0 0 0 0.012 0.047 0.024 0.107 0.107
BLD12F5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
BLD12F6 NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
BLU321 0.026 0.016 0.013 0.023 0.005 0.016 0.003 0.018 0 0.010 0.005 0.109 0.016 0.010 0.005 0.116 0.287 0.067
BLU322 0.039 0.024 0.016 0.024 0 0.008 0 0.016 0.008 0.024 0 0.087 0 0 0.024 0.087 0.623 0.032
BUN423 0.100 0.025 0 0.025 0.025 0.050 0.025 0.050 0.025 0.025 0 0.025 0.025 0.050 0 0.100 0.100 0.075
BUN424 0 0 0 0 0 0 0 0 0 0 0 0.078 0 0 0.039 0.039 0.233 0.039
BUN426 0.019 0.152 0.038 0.076 0 0.019 0.019 0.152 0.019 0.038 0.019 0 0 0.019 0.019 0.057 0.114 0.152
CDA123 0.008 0.015 0.054 0.054 0 0.008 0.008 0.015 0.046 0.015 0.008 0.108 0.008 0.023 0.015 0.132 0.774 0.054
CDA125 0 0.127 0.020 0.039 0.010 0 0.029 0.127 0.029 0.020 0.029 0.059 0.049 0.020 0 0.117 0.536 0.068
CFD1210 0.212 0.234 0.032 0.011 0.021 0.021 0.011 0.011 0.011 0 0 0.011 0.011 0 0.032 0 0.021 0.106
CFD1211 0.028 0.068 0.006 0.017 0.006 0.006 0.006 0 0.011 0.006 0.011 0.023 0.028 0.011 0.023 0 0.023 0.051
CGC331 0 0 0 0 0 0 0 0 0 0 0 0.095 0 0 0 0 0.190 0
CHE121=1 0.010 0.077 0.039 0 0.010 0.010 0.010 0.029 0 0 0 0.068 0.010 0.010 0 0.135 0.396 0.077
CHE12F4 0.026 0.034 0 0.009 0 0 0.009 0.009 0.009 0 0.017 0.052 0.009 0.043 0.009 0.121 0.259 0.034
TM
Page 12 2407043.000-9196 ��

October 30, 2024
Feeder Specific Ro (outages/yr./mi.)
ANIMAL EQUIPMENT OH PUBLIC TREE WEATHER UNDETER-
MINED
U
N L N
`o o =3 E ° c
5 `m a -0 `-' `m
LL
Feeder -a c c ° c = a) (D m O C-o En 3 m
Name* m �n a` ci ci ii o in � in D
CHW12F2 0.076 0.037 0.003 0.009 0 0.033 0.021 0.012 0.006 0.015 0.006 0.061 0.012 0.018 0.049 0.064 0.055 0.152
CHW12F3 0.026 0.021 0.003 0.005 0.002 0.016 0.011 0.007 0.007 0 0 0.051 0.003 0.016 0.015 0.102 0.082 0.130
CHW12F4 0.048 0.030 0.003 0.010 0 0.028 0.008 0.005 0.005 0.005 0.005 0.050 0.005 0.003 0.033 0.098 0.103 0.196
CKF711 0.023 0.023 0.005 0.009 0 0.019 0.014 0.009 0 0.005 0 0.107 0.014 0.014 0.014 0.009 0.173 0.042
CKF712 0.049 0.038 0 0 0 0.005 0.011 0.005 0.005 0.005 0 0.070 0.005 0.005 0.022 0.032 0.291 0.054
CLA56 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.046 0.015
CLV12F2 0.020 0.037 0.010 0.013 0.017 0.023 0.010 0.020 0.013 0.023 0.007 0.053 0.007 0.017 0.017 0.067 0.073 0.104
CLV12F4 0.077 0.040 0.009 0.006 0.020 0.031 0.014 0.014 0.014 0.003 0.006 0.049 0.006 0.017 0.020 0.086 0.083 0.140
CLV34F1 0.038 0.006 0.010 0.004 0.004 0.035 0.010 0.007 0.006 0.008 0.001 0.064 0.003 0.017 0.045 0.088 0.080 0.143
COB12F1 0.026 0.046 0.013 0 0.020 0.013 0.007 0 0.007 0.007 0 0.065 0.013 0.033 0.026 0.124 0.163 0.052
C0612F2 0.059 0.009 0.015 0.006 0.006 0.006 0.006 0.027 0.012 0.003 0 0.006 0.009 0.006 0.024 0.062 0.035 0.053
COT2401 0.035 0.014 0 0 0.021 0.014 0.028 0.028 0 0 0.007 0.007 0.014 0 0.014 0.035 0.049 0.028
CRG1261 0.004 0.004 0 0.004 0.004 0.004 0.011 0 0.015 0 0 0.011 0.004 0.004 0.038 0.019 0.023 0.034
DAL131 0.057 0.081 0.049 0.024 0.016 0.016 0.008 0.016 0.016 0.040 0.008 0.049 0.016 0.016 0.008 0.040 0.429 0.049
DAL132 0 0.063 0.126 0 0 0.063 0 0.189 0.032 0.063 0 0 0 0.032 0 0 0.790 0
DAL133 0.012 0.061 0.012 0.012 0 0 0.012 0.012 0.012 0.024 0.024 0.134 0 0.049 0 0.012 0.268 0.061
DAL135 0.052 0.069 0 0 0 0.035 0 0 0.017 0 0 0.017 0.017 0 0.017 0 0.225 0.035
DAL136 0.020 0.020 0 0.039 0 0.020 0.020 0.020 0 0.020 0 0.020 0 0 0 0 0.610 0
DEP12F1 0.050 0.013 0.003 0.010 0 0.018 0.008 0.013 0.010 0.008 0.003 0.013 0.003 0.008 0.030 0.085 0.063 0.038
DEP12F2 0.070 0.021 0 0.014 0.007 0.004 0.007 0.018 0.007 0.007 0 0.007 0.007 0 0.028 0.063 0.074 0.056
DER651 0.007 0 0.003 0.003 0.003 0.014 0.007 0 0.003 0.007 0.003 0.109 0.007 0.044 0.017 0.150 0.095 0.051
DER652 0.013 0.021 0 0.004 0.004 0.017 0.004 0.013 0.009 0 0 0.056 0.013 0.043 0.017 0.142 0.060 0.099
DRY1208 0.039 0.169 0.013 0.013 0.013 0 0.013 0.065 0.026 0.013 0.026 0.039 0.013 0 0.104 0 0.013 0.039
DRY1209 0.039 0 0.013 0.004 0.013 0.004 0.004 0.009 0.034 0 0 0.004 0 0 0.022 0.004 0.065 0.065
EFM12F1 0.087 0.045 0.014 0.010 0.003 0.007 0.007 0.010 0.010 0 0.003 0.017 0.007 0.003 0.014 0.024 0.076 0.062
EFM12F2 0.061 0.061 0 0.020 0.020 0.020 0.020 0 0 0 0 0 0 0 0 0 0.041 0
F&C12F2 0.079 0.013 0.013 0.066 0 0.013 0 0.026 0.013 0 0.013 0.026 0.013 0 0.026 0.079 0.185 0.013
FOR12F1 0.007 0.007 0.007 0 0.002 0.007 0.002 0.015 0.020 0.002 0 0.017 0.002 0 0.015 0.039 0.015 0.034
FOR121F2 0.004 0 0.004 0 0 0.004 0.004 0 0.029 0 0 0.022 0 0.004 0.007 0.029 0.076 0.004
FWT12F2 0.038 0.077 0.013 0.051 0.026 0.038 0 0.051 0.026 0.013 0 0.013 0.026 0.038 0.038 0.218 0.243 0.077
FWT12F3 0.030 0.060 0 0.030 0 0 0.120 0 0.015 0.015 0.045 0.015 0.015 0.015 0.030 0.210 0.389 0.045
GIF12F1 0.025 0.002 0.004 0.004 0.006 0.008 0.002 0.004 0.008 0 0 0.041 0.002 0.031 0.025 0.118 0.091 0.079
GIF34F1 0.044 0.004 0.005 0.005 0.005 0.012 0.004 0.003 0.005 0.001 0.001 0.027 0.002 0.003 0.028 0.038 0.061 0.099
GIF34F2 0.008 0.016 0.001 0.004 0.003 0.021 0.005 0.003 0.009 0.003 0.001 0.044 0.001 0.017 0.017 0.137 0.122 0.095
GLN12F1 0.015 0.122 0.005 0.046 0.010 0.026 0.015 0.026 0.026 0.015 0.020 0.077 0.041 0.015 0.026 0.602 0.230 0.122
GLN12F2 0.054 0.070 0.023 0.016 0 0 0.016 0.023 0 0 0.008 0.054 0.023 0.016 0 0.062 0.202 0.070
GRA12F1 0.087 0.034 0.013 0.027 0.020 0 0.020 0.040 0 0 0.013 0.027 0.013 0.020 0.013 0.013 0.087 0
GRA12F2 0.079 0.084 0.030 0.035 0.005 0.010 0.015 0.025 0.010 0.015 0.005 0.020 0.015 0.005 0.035 0.060 0.169 0.084
GRA12F3 0 0.084 0 0.042 0 0.042 0 0.155 0.014 0.028 0.014 0.028 0 0.014 0.028 0 0.112 0.028
GRN12F1 0.041 0.027 0.005 0.009 0.005 0.059 0.018 0.018 0.023 0.005 0 0.068 0.009 0.005 0.045 0.082 0.073 0.154
GRN121`2 0.036 0.033 0.004 0.007 0.015 0.025 0.004 0.015 0.011 0.004 0.004 0.047 0.007 0.022 0.047 0.112 0.080 0.170
GRN12F3 NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN
GRV1271 0 0.035 0.018 0.012 0.006 0.012 0.006 0.006 0.006 0.012 0 0.065 0.012 0 0.012 0.071 0.041 0.041
GRV1272 0 0.034 0 0.017 0 0.034 0.034 0 0.034 0.017 0.017 0.017 0.034 0 0 0.102 0.034 0.051
GRV1273 0.014 0.006 0 0.004 0 0.021 0 0.002 0.008 0.006 0 0.068 0.010 0.008 0 0.054 0.016 0.060
GRV1274 0.037 0.110 0.025 0.025 0 0.012 0 0 0.049 0 0.025 0.025 0.012 0 0.012 0.123 0.061 0.037
H&W12F1 0.029 0 0 0 0 0 0.014 0.057 0.029 0 0 0 0 0 0.014 0 0.029 0.014
H&W12F3 0.023 0.028 0 0.005 0 0.014 0.014 0.019 0.019 0.005 0 0.005 0 0.023 0.033 0.028 0.108 0.028
HUE141 0.062 0.021 0.062 0.021 0.010 0.021 0 0.062 0.021 0.031 0.010 0.021 0.021 0.021 0.021 0.021 0.312 0.062
HUE142 0.068 0.010 0.029 0 0 0.029 0.010 0.068 0 0.010 0 0.010 0 0 0.019 0.058 0.087 0.068
IDR251 0.043 0.021 0 0.021 0 0 0 0.043 0 0 0 0 0 0 0 0 0 0
IDR253 0.047 0.060 0.021 0.004 0.017 0.017 0 0.072 0.009 0.009 0 0.017 0.004 0.004 0.009 0.060 0.192 0.081
INT12F1 0 0 0 0 0 0 0.097 0 0.291 0 0 0 0 0 0 0 0.485 0.097
INT12F2 0.018 0.018 0 0 0.006 0 0.006 0.012 0.006 0.018 0 0.018 0 0.006 0.006 0 0.036 0.048
JUL661 0 0.009 0 0 0 0.009 0.027 0.036 0.009 0.009 0.009 0.054 0.018 0.018 0.063 0.018 0.027 0.063
JUL662 0.006 0.036 0.012 0 0 0 0.012 0.012 0.006 0 0 0.024 0.012 0 0.012 0.030 0.036 0.047
KAM1291 0 0.068 0 0.011 0.011 0.023 0.011 0.023 0.045 0.011 0.011 0.045 0.023 0 0.101 0.034 0.034 0.079
TM
Page 13 2407043.000-9196 ��

October 30, 2024
Feeder Specific Ro (outages/yr./mi.)
ANIMAL EQUIPMENT OH PUBLIC TREE WEATHER UNDETER-
MINED
U
N L N
`o o =3 E ° c
5 `m a -0a m °' 9 o `LL (D
Feeder A= c c o c = _ a) a) m U
Name* m �n a` ci 0, lz o in it � in D
KAM1292 0 0 0 0 0.016 0.016 0 0.016 0.016 0 0 0.033 0 0 0.066 0.049 0.049 0.181
KAM1293 0.011 0.032 0.043 0.011 0.011 0.011 0.032 0 0.011 0 0.011 0.043 0 0.011 0.086 0.064 0.054 0.075
KET12F1 0 0 0 0.052 0 0 0.052 0 0.104 0 0 0 0 0.052 0.259 0.259 0.052 0
KET12F2 0.037 0.016 0.004 0.002 0.002 0.012 0.009 0 0.032 0.005 0 0.035 0.002 0.005 0.042 0.070 0.079 0.119
K001298 0.006 0.012 0.006 0 0 0 0.018 0.006 0.025 0 0.006 0.043 0 0.006 0.012 0.049 0.018 0.018
K001299 0.043 0.006 0 0 0.019 0.031 0.006 0 0.006 0.006 0.012 0.025 0.006 0.006 0.012 0.019 0.025 0.081
L1312F1 0 0 0 0 0 0 0 0.016 0 0 0 0 0 0 0.016 0.016 0 0.032
LIB12F2 0.112 0 0.014 0 0 0.014 0 0.014 0 0.014 0.014 0 0 0 0.014 0.014 0.140 0.042
LIB12F3 0.044 0.051 0 0.022 0 0 0.007 0 0.022 0.044 0.022 0.059 0.007 0.015 0 0.029 0.139 0.102
LOL1266 0.015 0.024 0.010 0 0 0 0.005 0.029 0.024 0.010 0.019 0.015 0.015 0 0.005 0.010 0.005 0.029
1-01-1359 0.047 0.031 0.010 0.005 0.010 0.010 0.016 0.021 0.031 0.005 0.005 0.052 0.026 0.005 0.037 0 0.021 0.089
L0012F1 0.006 0.042 0.006 0.018 0 0.006 0.006 0.024 0.018 0.012 0 0.036 0.012 0.006 0.012 0.060 0.079 0.073
L0012F2 0.014 0.070 0 0.007 0.007 0 0.014 0 0.021 0.007 0.007 0.077 0.007 0.028 0.007 0.146 0.042 0.077
LTF34F1 0.020 0 0.002 0.004 0.006 0.006 0.004 0.004 0.004 0 0 0.026 0 0.004 0.018 0.032 0.074 0.044
M15514 0.019 0.107 0 0.069 0.006 0.019 0 0.032 0.038 0.006 0.019 0.025 0.013 0.057 0.013 0.164 0.234 0.063
M15515 0.024 0.033 0 0.016 0.016 0.008 0 0.033 0.049 0.033 0.008 0.008 0 0.008 0 0.041 0.049 0.073
M23621 0.016 0.005 0 0.011 0.011 0 0 0.011 0 0.005 0 0.044 0.011 0.033 0.005 0.065 0.054 0.071
MEA12F1 0 0.038 0 0 0 0 0.038 0.058 0.019 0.019 0 0.019 0.019 0.019 0.115 0.096 0.154 0.038
MEA12F2 0.042 0.116 0.011 0.021 0.021 0 0.021 0.011 0.032 0.011 0.032 0.095 0.053 0.042 0.042 0.063 0.168 0.074
MEA12F3 0 0.054 0 0 0 0 0 0 0.027 0 0 0 0 0 0 0.027 0.054 0
MIL121`3 0.127 0.064 0.025 0.038 0 0 0.013 0.038 0.013 0.013 0.025 0 0 0 0.064 0.114 0.102 0.064
MIS431 0.018 0.002 0.005 0.014 0.011 0.014 0.005 0.007 0.007 0.011 0.002 0.072 0.002 0.009 0.023 0.081 0.221 0.047
MLN12F1 0.014 0.031 0.007 0.010 0 0.017 0.007 0.041 0.017 0.007 0 0.024 0 0.014 0.010 0.099 0.075 0.038
MLN12F2 0.008 0.027 0 0.012 0.008 0.012 0.008 0 0.008 0 0.004 0.019 0 0.031 0.008 0.058 0.116 0.027
NE12F3 0.034 0.056 0.017 0 0.006 0.022 0 0.050 0.028 0.011 0.006 0.034 0.017 0.006 0.006 0.050 0.173 0.017
NE12F4 0.042 0.042 0.007 0.049 0.021 0.021 0 0.064 0.028 0.035 0.021 0.028 0 0.007 0.007 0.035 0.078 0.056
NRC351 0.067 0.067 0 0 0 0 0 0 0 0 0 0.067 0 0 0.067 0.133 0 0.200
NW12F1 0.0100.0670 0.019 0.010 0.019 0.010 0.038 0.029 0.010 0 0.019 0.029 0.019 0.019 0.029 0.200 0.048
NW12F2 0.064 0.140 0.025 0.025 0 0.013 0.051 0.025 0.038 0.013 0 0.089 0.025 0 0.038 0.254 0.496 0.025
NW12F3 0.011 0 0 0.033 0 0 0 0.033 0.022 0.011 0 0.033 0.022 0.033 0 0.089 0.301 0.022
ODN731 0.034 0.014 0.041 0.003 0.007 0.014 0.021 0.014 0.007 0.017 0.007 0.106 0.014 0.014 0 0.082 0.216 0.058
ODN732 0 0.032 0.021 0 0 0.011 0 0.021 0 0.011 0.011 0.086 0 0.043 0 0.021 0.428 0.043
OLD721 0.077 0.027 0.018 0 0.005 0.014 0.009 0.023 0.023 0.023 0.009 0.055 0.005 0.023 0 0.032 0.136 0.064
0RI12F1 0.023 0.020 0.005 0.005 0 0.023 0.005 0.008 0.008 0.005 0 0.067 0.005 0.018 0.028 0.105 0.097 0.102
ORI12F2 0.057 0.057 0 0.029 0.029 0 0 0 0 0 0 0 0.029 0 0.057 0.057 0.115 0.057
OR112F3 0.018 0.015 0.003 0.005 0.003 0.030 0.008 0 0.010 0 0.002 0.099 0.007 0.016 0.048 0.115 0.095 0.094
OR01280 0 0 0 0.072 0 0.036 0.018 0 0.036 0 0 0.090 0 0.018 0 0.018 0.271 0.036
OR01281 0.005 0.011 0.011 0.011 0 0.033 0.011 0 0.011 0.005 0 0.126 0.005 0.016 0.055 0.027 0.071 0.082
OR01282 0 0.056 0 0.022 0.011 0.022 0 0.011 0.022 0.011 0.011 0.056 0 0 0.022 0.011 0.112 0.078
OSB521 0.009 0.009 0 0.028 0.009 0 0.009 0.019 0.019 0.009 0.009 0.047 0.028 0 0.019 0.056 0.224 0
OSB522 0 0 0 0 0 0 0 0 0 0 0 0.194 0 0 0 0.097 0.024 0
PDL1202 0.039 0.193 0.010 0.048 0.048 0.019 0.029 0.048 0.077 0.048 0.077 0.048 0.058 0 0.097 0 0.106 0.058
PDL1203 0.069 0.233 0 0.043 0.026 0.026 0.043 0.034 0.060 0.034 0.017 0.034 0.009 0.017 0.043 0 0.069 0.086
PDL1204 0.018 0.072 0 0.036 0 0.036 0 0.054 0.018 0.018 0 0 0.018 0 0.018 0.018 0.018 0.036
PF212 0.030 0.163 0.059 0.030 0.015 0 0 0.015 0.015 0.015 0 0.015 0.030 0.030 0.045 0.015 0.282 0.059
PF213 0.066 0.121 0.011 0.011 0 0 0.022 0.055 0.044 0.022 0.011 0.044 0.033 0 0 0 0.165 0.066
PIN441 0 0.079 0.079 0.008 0.039 0.031 0.008 0.016 0.047 0 0.008 0.071 0 0.024 0.008 0.228 0.401 0.063
PIN442 0 0.037 0 0 0 0 0.056 0.019 0.056 0 0.019 0.093 0 0.037 0.037 0.037 0.243 0
PIN443 0.013 0.076 0.016 0.009 0.009 0.009 0.003 0.019 0.003 0.009 0.003 0.041 0 0.016 0.013 0.123 0.240 0.047
PRA221 0 0 0.045 0.045 0 0.045 0.022 0.067 0.022 0 0 0 0 0 0 0 0.067 0.090
PRA222 0.079 0.132 0 0 0 0.026 0 0.026 0.040 0.013 0.013 0.053 0 0 0.013 0 0.290 0.079
PRV751 0.025 0 0.025 0 0.013 0.013 0.025 0 0 0.013 0 0.075 0 0.038 0.013 0.050 0.213 0.013
PRV752 0.026 0.003 0.009 0.003 0.006 0.003 0.003 0.009 0.009 0.006 0.003 0.057 0 0.009 0.006 0.043 0.164 0.040
PVW241 0.071 0.071 0.007 0 0.057 0.014 0 0.042 0.021 0 0 0 0 0 0.007 0 0.078 0.113
PVW243 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
RAT233 0.012 0.014 0.009 0.007 0.009 0.021 0.005 0.035 0.012 0.009 0.005 0.051 0.005 0.002 0.012 0.105 0.135 0.056
RDN12F1 0.029 0.008 0.004 0.004 0.006 0.006 0.004 0.006 0.006 0 0.002 0.002 0.002 0.004 0.025 0.019 0.017 0.031
TM
Page 14 2407043.000-9196 ��

October 30, 2024
Feeder Specific Ro (outages/yr./mi.)
ANIMAL EQUIPMENT OH PUBLIC TREE WEATHER UNDETER-
MINED
U
cn a` �
y t �
`o o =3 E ° 0
c
Feeder A= o _ z a) a) o
3 v m
Name* m �n a` 0 US ii o in in D
RDN12F2 0.008 0.004 0.002 0.004 0.011 0.015 0 0.004 0.002 0.002 0 0.013 0 0.002 0.004 0.023 0.017 0.019
SAG741 0.012 0.015 0.030 0.009 0 0.006 0.012 0.045 0.003 0.015 0.003 0.185 0.009 0.027 0.021 0.098 0.426 0.021
SAG742 0.031 0.067 0.021 0 0.005 0.005 0.016 0.041 0.005 0 0.021 0.078 0.016 0.010 0.016 0.052 0.393 0.057
SE12F2 0.065 0.032 0 0.016 0.008 0.008 0.008 0.016 0.032 0.024 0.016 0 0.008 0.008 0.008 0.040 0.202 0.040
SE121`4 0 0.084 0.028 0.042 0.028 0.014 0 0.028 0.028 0.028 0.014 0.056 0.042 0.028 0.028 0.294 0.547 0.042
SE12F6 0 0.084 0.056 0.056 0 0 0 0 0 0 0 0 0 0 0 0 0.028 0.056
SIP12F3 0.118 0 0.039 0 0 0 0.039 0.079 0 0 0 0 0 0 0 0 0 0.158
SIP12F4 0.134 0.149 0.015 0.015 0.015 0.060 0.007 0.052 0.060 0.030 0.037 0.022 0.007 0.015 0.037 0.007 0.082 0.112
SLK121`1 0.037 0.048 0.007 0.015 0 0.004 0.004 0.007 0.029 0.011 0.018 0.022 0.007 0 0.004 0.011 0.037 0.077
SLK12F2 0.057 0.015 0.011 0.004 0.015 0.019 0.008 0.008 0 0.004 0 0.008 0.008 0.004 0.015 0.011 0.159 0.079
SLK12F3 0.018 0 0 0 0.018 0.009 0 0.044 0.018 0.009 0 0.009 0 0 0.009 0.009 0.009 0.026
SLW1348 0.087 0.319 0 0.116 0 0 0.029 0 0 0 0.116 0.029 0 0 0.029 0 0.087 0
SLW1358 0.063 0.295 0.021 0.011 0.021 0.032 0.021 0.021 0.021 0.032 0.084 0.042 0.011 0.021 0.032 0.011 0.042 0.063
SLW1368 0.059 0.163 0.030 0.044 0.015 0.030 0.015 0.015 0.044 0 0.015 0.030 0.015 0.015 0.030 0.015 0.119 0.030
SOT521 0.069 0.228 0.010 0.020 0.020 0.069 0.010 0.059 0.059 0.030 0.010 0.020 0.020 0 0.010 0 0.079 0.119
SOT523 0.106 0.032 0 0.007 0.018 0.009 0.012 0.009 0.002 0.005 0 0.016 0.007 0.002 0.021 0.002 0.037 0.101
SPI121`1 0.029 0.002 0 0.004 0.004 0.002 0 0.002 0.018 0.009 0.007 0.022 0.002 0.007 0.009 0.029 0.057 0.044
SPL361 0.019 0.050 0 0.044 0.006 0.019 0.012 0.025 0.006 0.012 0.069 0.125 0.006 0.031 0.006 0.087 0.406 0.075
SPT4S21 0.016 0.054 0.037 0.004 0.004 0.021 0.008 0.012 0.004 0.004 0.004 0.103 0.012 0.066 0.016 0.049 0.334 0.091
SPT4S23 0.007 0.047 0.020 0.007 0.007 0.007 0 0.014 0.041 0.007 0.014 0.061 0 0 0.014 0.034 0.359 0.068
STM631 0.043 0.015 0.006 0.009 0.009 0.046 0.006 0.018 0.015 0 0.006 0.114 0.018 0.009 0.021 0.233 0.215 0.061
STM633 0.032 0.007 0.002 0.012 0.010 0.049 0.010 0.017 0.005 0.007 0.005 0.090 0.010 0.015 0.034 0.234 0.124 0.095
STM634 0.003 0 0.003 0.003 0 0.008 0 0 0.006 0.003 0 0.031 0 0 0.011 0.025 0.059 0.039
SUN12F1 0 0.060 0 0.048 0 0 0.012 0.036 0.024 0.012 0.024 0.084 0.060 0.024 0.012 1.222 0.863 0.060
SUN12F2 0.012 0.046 0.006 0 0 0.017 0 0.006 0.017 0.023 0.012 0.006 0.006 0.023 0.046 0.110 0.151 0.069
SUN12F4 0.019 0.019 0.006 0.019 0.006 0.026 0 0.045 0.013 0 0.006 0.013 0 0 0 0.083 0.083 0.032
SUN12F5 0.042 0.004 0.023 0.004 0 0.008 0.008 0.011 0.015 0.004 0 0.023 0.015 0.008 0.015 0.065 0.103 0.027
SWT2403 0.014 0.005 0.009 0 0.009 0.005 0 0.036 0.018 0.005 0 0.005 0.014 0 0.005 0.005 0.027 0.059
TEN1253 0.032 0 0.064 0.032 0 0.032 0 0.032 0 0.032 0.032 0 0 0 0 0 0.032 0.095
TEN1254 0.049 0.029 0.019 0.029 0 0 0.019 0.058 0.058 0.010 0.039 0.010 0.029 0 0.029 0.010 0.039 0.029
TEN1255 0.023 0.058 0.035 0.070 0.012 0 0 0.081 0.070 0.070 0 0.058 0.023 0 0.023 0 0.093 0.093
TEN1256 0.045 0 0.009 0 0.009 0 0.009 0.045 0.018 0.018 0.009 0.045 0 0 0.018 0 0.018 0.136
TEN1257 0.052 0.069 0.034 0.017 0.017 0 0.017 0.043 0.043 0.026 0.009 0.026 0 0 0.086 0 0 0.026
VAL12F1 0.007 0.015 0.006 0.004 0.003 0.017 0.004 0.017 0.017 0.007 0.003 0.037 0 0.028 0.017 0.117 0.069 0.118
VAL12F2 0.082 0.051 0 0.021 0.005 0.010 0.010 0.015 0.021 0.010 0.005 0.051 0.005 0.005 0.046 0.113 0.087 0.257
VAL121`3 0.032 0.042 0.005 0.011 0 0.037 0.026 0.042 0.016 0.021 0.021 0.042 0.011 0.047 0.016 0.137 0.131 0.184
WAK12F1 0.029 0.118 0.044 0 0 0.015 0.029 0.015 0 0.029 0.015 0.074 0.015 0 0.133 0.118 1.430 0.074
WAK121`2 0.026 0.026 0 0 0 0 0 0.064 0.013 0.013 0 0.052 0.039 0.026 0.013 0.090 0.129 0.026
WAK12F3 0 0.031 0.015 0.031 0.015 0 0 0.015 0.015 0.031 0.015 0.031 0.061 0.015 0.061 0.092 0.275 0.076
WAK12F4 0.039 0.019 0.010 0 0 0.010 0.010 0.019 0.010 0 0.0190.0390 0.019 0.010 0.087 0.107 0.155
WAL542 0.011 0.023 0.011 0.011 0.011 0 0.011 0.023 0.023 0.011 0 0.080 0.011 0.011 0 0.080 0.034 0.034
WAL543 0.004 0.016 0.008 0.004 0.004 0.016 0 0.012 0.012 0.004 0 0.140 0.004 0.029 0.016 0.095 0.115 0.025
WAL544 0.048 0.060 0.012 0.036 0.012 0.036 0 0 0.024 0.012 0 0.048 0.024 0 0 0.084 0.084 0.072
WAL545 0.012 0.012 0.023 0.012 0 0.035 0.012 0 0.046 0.012 0.023 0.104 0 0.012 0 0.058 0.150 0.046
WAS781 0.026 0 0 0.009 0.004 0.004 0.009 0.004 0.013 0.004 0 0 0.004 0 0.013 0.004 0.026 0.035
WE11289 0.004 0.011 0.004 0.011 0 0.007 0.007 0.011 0 0.004 0.011 0.076 0.011 0.036 0.025 0.079 0.029 0.036
WIL12F2 0.020 0 0.005 0.005 0.029 0.022 0.002 0.003 0.008 0 0 0.005 0 0 0.005 0.005 0.017 0.022
*NaN parameters indicate that outage data was not available for the feeder. In these cases,the system-wide outage rate was used
for analysis.
TM
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Table 3. Proportion Mitigation Effectiveness due to Undergrounding
Outage Reason: ME, Reasoning
Subreason
ANIMAL: Bird 1 not applicable to underground lines
ANIMAL:Other 1 not applicable to underground lines
ANIMAL: Protected 1 not applicable to underground lines
ANIMAL:Squirrel 1 not applicable to underground lines
COMPANY:Other 0.5 undergrounded lines require less frequent maintenance
EQUIPMENT OH: 0.8 undergrounded lines have fewer arresters that are typically installed at transition points or
Arrester critical equipment locations and have lower maintenance requirements
EQUIPMENT OH: 0'8 undergrounded lines have fewer capacitors for reasons including a stable operating
Capacitor environment and an inherently more efficient design
EQUIPMENT OH: 0.8 underground conductors experience fewer outages because they are more protected,but
Conductor-Pri outages do occur(e.g.,from construction or water intrusion)
EQUIPMENT OH: 0'8 underground conductors experience fewer outages because they are more protected,but
Conductor-Sec outages do occur(e.g.,from construction or water intrusion)
EQUIPMENT OH: 0'8 underground lines have fewer connectors since there are longer continuous sections and
Connector-Pri stable environmental conditions.
EQUIPMENT OH: 0.8 underground lines have fewer connectors since there are longer continuous sections and
Connector-Sec stable environmental conditions.
EQUIPMENT OH: 1 not applicable to underground lines
Crossarm-rotten
EQUIPMENT OH: 1 underground lines no not use overhead style cutouts or fuses and instead use alternative
Cutout/Fuse protective devices such as circuit breakers or protective relays
EQUIPMENT OH: underground lines have fewer insulators due to integrated cable insulation and fewer
Insulator 0'8 installation points
EQUIPMENT OH: 1 not applicable to underground lines(insulator pins are for overhead lines to support and
Insulator Pin secure the insulators)
EQUIPMENT OH:Other 0.5 underground lines have fewer equipment related outages due to reduced exposure to
physical damage and enhanced durability(robust insulation and protective sheaths)
EQUIPMENT OH: Pole- 1 not applicable to underground lines
rotten
EQUIPMENT OH: 1 underground lines generally do not use reclosers except in some advanced or specialized
Recloser installations of reclosers designed for underground environments
EQUIPMENT OH: underground lines have fewer regulators which reflects a reduced need for voltage
Regulator 0.6 regulation due to the stability of underground environments and higher cost and installation
complexity
EQUIPMENT OH: underground lines have fewer switches or disconnects due to less frequent switching points
Switch/Disconnect 0'4 and the higher cost and complexity to install/maintain
EQUIPMENT OH: underground lines have fewer transformers dur to higher cost and complexity of
Transformer-OH 0.5 installations,different design and distribution requirements,and reduced environmental
exposure.
EQUIPMENT OH:Wildlife1 not applicable to underground lines
Guard
MISCELLANEOUS:SEE 0 without more information this category is considered unmitigated by undergrounding
REMARKS
POLE FIRE: Pole Fire 1 not applicable to underground lines
PUBLIC:Car Hit Pole 1 not applicable to underground lines
PUBLIC: Fire 0 in the event of a house fire,either overhead or underground lines will be deenergized
PUBLIC:Other 0.8 outages related to the public are reduced by undergrounding since the lines are protected,
however there can still be outages(e.g.,from construction or vandalism/theft)
PUBLIC:Tree 1 underground lines are protected from tree related outages
TREE:Service 1 underground lines are protected from tree related outages
TREE:Tree Fell 1 underground lines are protected from tree related outages
TREE:Tree Growth 1 assuming canopy growth and not root growth, underground lines are protected from tree
related outages
TREE:Weather 1 underground lines are protected from tree related outages
TM
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Outage Reason: ME, Reasoning
Subreason
WEATHER: Heat 0 when capacity is constrained on the grid,the load will be dropped for either overhead or
underground lines
WEATHER:Lightning 0.8 underground lines are less vulnerable to lightning damage,but ground strikes and voltage
surges can occur
underground lines are generally protected from snow/ice damage(snow and ice do not
WEATHER:Snow/Ice 1 have a direct effect on underground lines,but winter weather does complicate
repair/maintenance and increased use of electricity in cold weather stresses the system)
WEATHER:Wildfire 0.5 underground lines mitigate wildfire risk,but overhead and underground lines are
deenergized when any wildfire approaches
WEATHER:Wind 1 underground lines are generally protected from wind damage
UNDETERMINED: 0.91 weighted average based on number of outages from other categories
Undetermined
Table 4. Example Outage Benefit Calculation for a Feeder
Feeder Outage RO LF CustTotF CIO Do ACOHF UGF MEo Mitigated CICOstF Mitigated
Name Reason: (outages/ (mi.) (hrs.) ACOHF AICOstF
Subreason yr./mi.)
9CE12F4 ANIMAL:Bird 0.01816 8.48 1020 0.037 1.69 9.93 0.257 1 2.55 $94.62 $241.41
9CE12F4 ANIMAL:Other 0.00327 8.48 1020 0.053 1.88 2.84 0.257 1 0.73 $94.62 $68.99
9CE12F4 ANIMAL:Protected 0.00018 8.48 1020 0.073 1.60 0.18 0.257 1 0.05 $94.62 $4.44
9CE12F4 ANIMAL:Squirrel 0.03632 8.48 1020 0.015 1.46 7.04 0.257 1 1.81 $94.62 $171.20
9CE12F4 COMPANY:Other 0.01059 8.48 1020 0.150 1.39 19.01 0.257 0.5 2.44 $94.62 $231.13
9CE12F4 EQUIPMENT OH: 0 8.48 1020 0.049 2.05 0 0 $94.62 $0.00
Arrester 0.257 0.8
9CE12F4 EQUIPMENT OH: 0.00018 8.48 1020 0.121 2.38 0.45 0.09 $94.62 $8.73
Capacitor 0.257 0.8
9CE12F4 EQUIPMENT OH: 0.01047 8.48 1020 0.149 3.24 43.62 8.97 $94.62 $848.59
Conductor-Pri 0.257 0.8
9CE12F4 EQUIPMENT OH: 0.03632 8.48 1020 0.005 2.01 3.04 0.62 $94.62 $59.09
Conductor-Sec 0.257 0.8
9CE12F4 EQUIPMENT OH: 0 8.48 1020 0.081 2.61 0 0 $94.62 $0.00
Connector-Pri 0.257 0.8
9CE12F4 EQUIPMENT OH: 0.00828 8.48 1020 0.004 1.82 0.51 0.11 $94.62 $9.95
Connector-Sec 0.257 0.8
9CE12F4 EQUIPMENT OH: 0.00164 8.48 1020 0.093 3.15 4.15 1.07 $94.62 $100.82
Crossarm-rotten 0.257 1
9CE12F4 EQUIPMENT OH: 0 8.48 1020 0.032 2.29 0 0 $94.62 $0.00
Cutout/Fuse 0.257 1
9CE12F4 EQUIPMENT OH: 0.00247 8.48 1020 0.226 2.92 14.12 2.90 $94.62 $274.62
Insulator 0.257 0.8
9CE12F4 EQUIPMENT OH: 0.00142 8.48 1020 0.102 2.86 3.58 0.92 $94.62 $87.12
Insulator Pin 0.257 1
9CE12F4 EQUIPMENT OH: 0.00373 8.48 1020 0.078 2.30 5.76 0.74 $94.62 $70.05
Other 0.257 0.5
9CE12F4 EQUIPMENT OH: 0.00112 8.48 1020 0.020 4.59 0.88 0.23 $94.62 $21.40
Pole-rotten 0.257 1
9CE12F4 EQUIPMENT OH: 0.00030 8.48 1020 0.523 2.38 3.23 0.83 $94.62 $78.47
Recloser 0.257 1
9CE12F4 EQUIPMENT OH: 0.00020 8.48 1020 0.339 2.60 1.52 0.23 $94.62 $22.21
Regulator 0.257 0.6
9CE12F4 EQUIPMENT OH: 0.00040 8.48 1020 0.417 1.40 2.01 0.21 $94.62 $19.54
Switch/Disconnect 0.257 0.4
9CE12F4 EQUIPMENT OH: 0 8.48 1020 0.025 3.88 0 0 $94.62 $0.00
Transformer-OH 0.257 0.5
9CE12F4 EQUIPMENT OH: 0.00002 8.48 1020 0.009 4.39 0.01 0.00 $94.62 $0.16
Wildlife Guard 0.257 1
9CE12F4 MISCELLANEOUS: 0.00114 8.48 1020 0.004 2.38 0.10 0 $94.62 $0.00
SEE REMARKS 0.257 0
9CE12F4 POLE FIRE:Pole 0.00890 8.48 1020 0.230 4.47 79.02 20.31 $94.62 $1,921.59
Fire 0.257 1
9CE12F4 PUBLIC:Car Hit Pole0.05447 8.48 1020 0.247 3.03 352.64 0.257 1 90.63 $94.62 $8,575.26
9CE12F4 PUBLIC:Fire 0.07263 8.48 1020 0.013 1.54 12.48 0.257 0 0 $94.62 $0.00
9CE12F4 PUBLIC:Other 0.03632 8.48 1020 0.040 1.82 22.65 0.257 0.8 4.66 $94.62 $440.69
TM
Page 17 2407043.000-9196 �/�'

October 30, 2024
Feeder Outage RO LF CustTotF CIO Do ACOHF UGF MEO Mitigated ClCostF Mitigated
Name Reason: (outages/ (mi.) (hrs.) ACOHF AlCostF
Subreason yr./mi.)
9CE12F4 PUBLIC:Tree 0.00403 8.48 1020 0.074 2.87 7.40 0.257 1 1.90 $94.62 $179.85
9CE12F4 TREE:Service 0.01816 8.48 1020 0.003 2.05 0.81 0.257 1 0.21 $94.62 $19.61
9CE12F4 TREE:Tree Fell 0.01816 8.48 1020 0.099 3.15 49.26 0.257 1 12.66 $94.62 $1,197.90
9CE12F4 TREE:Tree Growth 0 8.48 1020 0.032 1.93 0 0.257 1 0 $94.62 $0.00
9CE12F4 TREE:Weather 0 8.48 1020 0.071 5.63 0 0.257 1 0 $94.62 $0.00
9CE12F4 UNDETERMINED: 0.07263 8.48 1020 0.098 2.10 129.57 30.26 $94.62 $2,863.44
Undetermined 0.257 0.91
9CE12F4 WEATHER:Heat 0.00004 8.48 1020 0.002 7.96 0.00 0.257 0 0 $94.62 $0.00
9CE12F4 WEATHER: 0.01816 8.48 1020 0.070 3.99 44.14 9.07 $94.62 $858.61
Lightning 0.257 0.8
9CE12F4 WEATHER: 0.05447 8.48 1020 0.063 10.29 305.57 78.53 $94.62 $7,430.67
Snow/Ice 0.257 1
9CE12F4 WEATHER:Wildfire 0.00030 8.48 1020 0.497 9.57 12.31 0.257 0.5 1.58 $94.62 $149.61
9CE12F4 WEATHER:Wind 0.10895 8.48 1020 0.074 17.22 1199.99 0.257 1 308.39 $94.62 $29,180.26
Feeder Total 2337.81 582.70 $55,135.41
Table 5. Outage Benefit Analysis Results for Feeders with Proposed Undergrounding
Feeder Name* LF (mi.) UGF Mitigated ACOHF ClCostF Mitigated AlCostF
9CE12F4 8.48 0.257 582.70 $94.62 $55,135
9CE12F6 16.99 0.136 4,259.97 $94.62 $403,078
A1R12F1 55.37 0.656 5,062.63 $94.62 $479,026
AIR121`2 13.77 0.353 1,506.36 $94.62 $142,532
AIR12F3 5.61 0.862 150.58 $94.62 $14,247
APW112 13.28 0.136 3,516.24 $127.37 $447,864
APW113 11.86 0.310 2,172.04 $127.37 $276,652
ARD12F2 56.13 0.179 2,312.64 $94.62 $218,822
AVD151 22.72 0.782 23,822.35 $127.37 $3,034,252
AVD152 11.55 0.099 994.38 $127.37 $126,654
BEA12F2 19.28 0.125 3,176.48 $94.65 $300,665
BEA13T09 1.14 0.098 0.07 $94.62 $6
BIG411 14.50 0.556 2,210.56 $127.37 $281,559
BIG412 6.55 0.340 283.23 $127.37 $36,074
BIG413 2.53 0.853 4.04 $127.37 $515
BKR12F1 5.15 0.083 290.16 $94.62 $27,455
BKR12F2 5.59 0.395 53.23 $94.62 $5,036
BKR12F3 11.51 0.185 469.81 $94.62 $44,453
BLA311 32.20 0.756 2,953.94 $125.72 $371,377
BLD12F4 13.00 0.909 6,047.88 $94.62 $572,250
BLD12F5 0.65 0.015 0.00 $94.62 $0
BLD12F6 1.04 0.520 0.31 $94.62 $30
BLU321 59.52 0.251 14,482.21 $127.37 $1,844,599
BLU322 19.51 0.972 13,205.76 $127.37 $1,682,018
BUN423 6.14 0.030 64.47 $127.37 $8,212
BUN424 3.97 0.844 37.04 $127.37 $4,718
BUN426 8.09 0.288 373.04 $127.37 $47,514
CDA123 19.88 0.251 14,327.47 $127.37 $1,824,890
CDA125 15.79 0.079 3,431.42 $127.37 $437,060
CFD1210 14.49 0.609 1,896.81 $94.62 $179,476
CFD1211 27.03 0.406 1,084.76 $94.62 $102,640
CGC331 1.62 0.307 3.48 $127.37 $443
CHE121`1 15.93 0.010 192.48 $94.62 $18,213
CHE12F4 17.86 0.566 8,303.39 $94.62 $785,667
CHW12F2 50.61 0.418 5,324.48 $94.62 $503,802
CHW12F3 93.76 0.207 3,720.09 $94.62 $351,995
CHW12F4 61.28 0.190 2,001.91 $94.62 $189,421
CKF711 33.02 0.549 5,573.93 $127.37 $709,951
CKF712 28.52 0.210 2,055.85 $127.37 $261,854
CLA56 9.95 0.815 19.83 NaN NaN
CLV12F2 46.08 0.470 7,635.74 $94.62 $722,493
CLV12F4 53.91 0.376 8,133.53 $94.62 $769,595
CLV34F1 207.44 0.139 12,538.89 $94.62 $1,186,430
T,
Page 18 2407043.000-9196 �TM

October 30, 2024
Feeder Name* LF (mi.) UGF Mitigated ACOHF CICOstF Mitigated A/CostF
COB12F1 23.63 0.819 15,611.87 $94.62 $1,477,195
COB12F2 52.05 0.897 14,660.71 $94.62 $1,387,196
COT2401 21.94 0.020 43.63 $127.37 $5,558
CRG1261 40.76 0.008 12.28 $127.37 $1,564
DAL131 19.02 0.479 13,158.38 $127.37 $1,675,982
DAL132 4.87 0.114 1,914.60 $127.37 $243,863
DAL133 12.65 0.748 6,277.74 $127.37 $799,596
DAL135 8.89 0.401 942.86 $127.37 $120,092
DAL136 7.83 0.345 3,697.06 $127.37 $470,895
DEP12F1 61.53 0.747 18,182.61 $94.62 $1,720,439
DEP12F2 43.80 0.516 8,680.69 $94.62 $821,367
DER651 45.28 0.111 922.93 $127.37 $117,554
DER652 35.90 0.370 1,953.12 $127.37 $248,768
DRY1208 11.83 0.351 741.92 $94.62 $70,200
DRY1209 35.78 0.429 443.12 $94.62 $41,928
EFM12F1 44.42 0.609 6,680.21 $95.95 $640,964
EFM12F2 7.52 0.755 519.88 $94.62 $49,191
F&C12F2 11.65 0.331 3,025.45 $94.62 $286,268
FOR12F1 62.83 0.922 3,494.44 $94.62 $330,644
FOR12F2 42.76 0.541 1,350.99 $94.62 $127,831
FWT12F2 12.03 0.036 554.68 $94.62 $52,483
FWT12F3 10.28 0.004 43.78 $94.62 $4,142
GIF12F1 79.53 0.108 1,612.53 $94.62 $152,578
GIF34F1 148.01 0.019 478.84 $94.62 $45,308
GIF34F2 114.86 0.267 9,891.06 $94.62 $935,892
GLN12F1 30.16 0.013 938.96 $94.62 $88,845
GLN12F2 19.78 0.625 11,769.76 $94.62 $1,113,655
GRA12F1 22.87 0.098 997.05 $94.62 $94,340
GRA12F2 31.04 0.690 14,216.81 $94.62 $1,345,194
GRA12F3 10.95 0.014 100.76 $94.62 $9,534
GRN12F1 33.97 0.483 5,723.35 $94.62 $541,543
GRN12F2 42.44 0.764 7,522.00 $94.62 $711,732
GRN12F3 0.36 0.021 0.00 NaN NaN
GRV1271 26.16 0.611 1,745.67 $127.37 $222,346
GRV1272 9.06 0.059 50.58 $127.37 $6,442
GRV1273 79.14 0.466 3,028.69 $127.37 $385,765
GRV1274 12.54 0.019 51.30 $127.37 $6,533
H&W12F1 10.78 0.533 87.94 $94.62 $8,321
H&W12F3 32.80 0.702 2,923.11 $94.62 $276,584
HUE141 14.79 0.105 1,632.05 $127.37 $207,875
HUE142 15.84 0.636 8,057.97 $127.37 $1,026,344
IDR251 7.16 0.920 154.89 $127.37 $19,729
IDR253 36.17 0.863 24,637.19 $127.37 $3,138,039
INT12F1 1.59 0.409 994.85 $94.62 $94,133
INT12F2 25.61 0.868 3,150.60 $94.62 $298,110
JUL661 17.01 0.009 10.08 $127.37 $1,284
JUL662 25.94 0.118 139.32 $127.37 $17,745
KAM1291 13.66 0.962 1,486.24 $127.37 $189,302
KAM1292 9.37 0.967 200.89 $127.37 $25,587
KAM1293 14.38 0.774 1,279.15 $127.37 $162,926
KET12F1 2.97 0.899 88.79 $94.62 $8,401
KET12F2 87.66 0.170 3,156.15 $94.62 $298,635
K001298 24.98 0.721 1,076.13 $127.37 $137,066
K001299 24.85 0.793 975.06 $127.37 $124,193
L1312F1 9.54 0.598 30.97 $94.62 $2,931
LIB12F2 11.00 0.494 927.97 $94.62 $87,805
LIB12F3 21.04 0.678 8,693.80 $96.08 $835,314
LOL1266 31.82 0.522 2,091.27 $127.37 $266,365
LOL1359 29.48 0.137 1,024.88 $127.37 $130,539
L0012F1 25.45 0.654 3,950.77 $94.62 $373,821
L0012F2 22.09 0.863 3,568.88 $94.62 $337,688
LTF34F1 77.21 0.411 2,464.67 $94.62 $233,207
M15514 24.37 0.075 3,023.79 $127.37 $385,141
M15515 18.87 0.035 238.84 $126.70 $30,261
M23621 28.29 0.038 162.04 $127.37 $20,639
MEA12F1 8.01 0.266 1,200.18 $94.62 $113,561
MEA12F2 14.66 0.897 8,172.88 $94.62 $773,318
MEA12F3 5.72 0.328 78.74 $94.62 $7,451
/
Page 19 2407043.000-9196 t. v M

October 30, 2024
Feeder Name* LF (mi.) UGF Mitigated ACOHF CICostF Mitigated AICostF
MIL12F3 12.12 0.224 1,718.96 $94.62 $162,648
MIS431 68.33 0.045 1,138.92 $127.37 $145,064
MLN12F1 45.06 0.958 9,635.73 $94.62 $911,732
MLN12F2 39.82 0.977 9,730.13 $94.62 $920,665
NE12F3 27.51 0.305 4,497.34 $94.62 $425,539
NE12F4 21.81 0.129 1,091.80 $94.62 $103,307
NRC351 2.31 0.227 2.33 $127.37 $296
NW12F1 16.14 0.445 5,401.95 $94.62 $511,133
NW12F2 12.11 0.324 4,987.15 $94.62 $471,884
NW12F3 13.79 0.178 2,475.91 $94.62 $234,271
ODN731 44.95 0.467 14,347.82 $127.37 $1,827,482
ODN732 14.39 0.305 585.89 $127.37 $74,625
OLD721 33.84 0.901 7,638.61 $127.28 $972,273
OR112F1 60.14 0.635 7,573.39 $94.62 $716,595
OR112F2 5.38 0.867 205.04 $94.62 $19,401
OR112F3 93.55 0.237 8,236.34 $94.62 $779,323
OR01280 8.53 0.964 2,104.35 $127.37 $268,031
OR01281 28.19 0.651 3,084.71 $127.37 $392,900
OR01282 13.78 0.573 1,039.14 $127.37 $132,355
OSB521 16.48 0.260 1,542.81 $127.37 $196,508
OSB522 6.35 0.813 9.89 $127.37 $1,259
PDL1202 15.95 0.039 357.99 $94.62 $33,873
PDL1203 17.86 0.096 537.48 $94.62 $50,857
PDL1204 8.55 0.724 509.82 $94.62 $48,239
PF212 10.37 0.023 180.41 $127.37 $22,979
PF213 14.00 0.146 1,412.45 $127.37 $179,904
PIN441 19.60 0.286 4,279.37 $127.37 $545,064
PIN442 8.23 0.422 780.19 $127.37 $99,372
PIN443 48.81 0.325 10,072.47 $127.37 $1,282,931
PRA221 6.86 0.111 160.02 $127.37 $20,382
PRA222 11.67 0.077 1,172.34 $127.37 $149,320
PRV751 12.31 0.709 1,976.77 $127.37 $251,781
PRV752 53.63 0.674 13,329.75 $127.37 $1,697,811
PVW241 21.76 0.461 3,541.34 $127.14 $450,258
PVW243 1.87 0.574 8.19 $127.37 $1,043
RAT233 66.24 0.755 47,014.80 $127.37 $5,988,275
RDN12F1 79.88 0.069 257.17 $94.62 $24,333
RDN12F2 72.66 0.057 104.45 $94.62 $9,883
SAG741 51.72 0.606 28,906.30 $127.37 $3,681,796
SAG742 29.75 0.676 18,356.61 $127.37 $2,338,081
SE12F2 19.04 0.534 9,598.86 $94.62 $908,244
SE12F4 10.99 0.206 4,290.51 $94.62 $405,968
SE12F6 5.49 0.113 58.46 $94.62 $5,532
SIP12F3 3.91 0.058 3.18 $94.62 $301
SIP12F4 20.67 0.050 577.10 $94.62 $54,605
SLK12F1 41.96 0.558 3,599.40 $94.62 $340,575
SLK12F2 40.70 0.233 2,397.83 $94.62 $226,883
SLK12F3 17.48 0.820 154.71 $94.62 $14,638
SLW1348 5.31 0.694 629.69 $127.37 $80,203
SLW1358 14.64 0.077 358.75 $127.37 $45,694
SLW1368 10.38 0.267 923.22 $108.10 $99,798
SOT521 15.54 0.188 825.79 $94.62 $78,136
SOT523 66.75 0.150 852.44 $94.62 $80,658
SPI12F1 70.20 0.047 404.41 $94.62 $38,266
SPL361 24.67 0.530 15,946.81 $127.37 $2,031,145
SPT4S21 37.33 0.759 28,279.23 $127.37 $3,601,926
SPT4S23 22.71 0.059 1,497.89 $127.37 $190,786
STM631 50.15 0.576 30,549.00 $127.33 $3,889,751
STM633 63.17 0.129 4,348.90 $127.37 $553,919
STM634 54.92 0.094 538.66 $127.37 $68,609
SUN12F1 12.85 0.053 4,290.49 $94.62 $405,966
SUN12F2 26.59 0.811 15,114.56 $94.62 $1,430,140
SUN12F4 24.03 0.458 5,017.56 $94.62 $474,761
SUN12F5 40.49 0.763 5,302.42 $94.62 $501,715
SWT2403 34.11 0.283 735.56 $127.37 $93,689
TEN1253 4.85 0.058 18.65 $127.37 $2,376
TEN1254 15.86 0.106 345.71 $127.37 $44,034
TEN1255 13.28 0.100 779.63 $127.37 $99,302
Page 20 2407043.000-9196 t x TM

October 30, 2024
Feeder Name* LF (mi.) UGF Mitigated ACOHF CICostF Mitigated A/CostF
TEN1256 16.98 0.290 587.35 $127.37 $74,810
TEN1257 17.86 0.089 338.27 $127.37 $43,085
VAL121`1 111.85 0.469 16,030.68 $94.62 $1,516,823
VAL12F2 30.00 0.560 2,034.90 $94.62 $192,542
VAL12F3 29.30 0.532 4,615.51 $94.62 $436,720
WAK12F1 10.44 0.589 28,438.44 $94.62 $2,690,845
WAK12F2 11.94 0.374 1,852.77 $94.62 $175,309
WAK12F3 10.08 0.133 1,200.69 $94.62 $113,609
WAK12F4 15.86 0.901 7,061.93 $94.62 $668,200
WAL542 13.55 0.115 167.31 $127.37 $21,310
WAL543 37.33 0.062 366.10 $127.37 $46,630
WAL544 12.86 0.595 1,066.57 $127.37 $135,850
WAL545 13.37 0.222 763.66 $127.37 $97,268
WAS781 34.93 0.106 63.78 $94.62 $6,035
WE11289 42.76 0.325 1,674.90 $127.37 $213,332
WIL12F2 90.56 0.009 33.96 $94.62 $3,213
Total 834,738.99 $92,801,089
'NaN results indicate that input data was not available for the feeder
60
50
40
LL
a�
a�
30
a�
E
n
Z 20
10
0
OM 1M 2M 3M 4M 5M 6M
Mitigated Interruption Cost($)/Year
Figure 5. Distribution of mitigated interruption costs per year for 195
feeders with proposed undergrounding.
Outage Direct Costs
The purpose of this analysis is to determine the direct costs related to resolving outages (and the
associated failures) for OH feeders that would be mitigated by undergrounding. The procedure to
determine the mitigated failures and outages' direct cost is described as follows:
Page 21 2407043.000-9196 t. V'TM

October 30, 2024
1. Avista provided the straight time rate (STR) of$1,077.49/hr. associated with resolving
outages. This rate considers the typical composition of one work crew and assumes that
only one crew is deployed for an outage. In reality, the number of crews can be greater
than one.
2. It is assumed that the crew is deployed for the duration of the outage.
3. The annual direct cost of outages that is mitigated (on a feeder) is calculated by summing
the reduced direct costs associated with all outage reasons and subreasons, and is termed
Mitigated ADCostF, which is calculated as follows:
Ototal
Mitigated ADCostF = Y, MEo RF,o UGLF Do STR
0=1
Where ototal is the number of outage reason and subreason combinations, ME, is the
mitigation effectiveness (proportion) of undergrounding to reduce outages for the outage
reason and subreason combination, RF,o is the feeder specific or system-wide outage rate
(outages/yr./mi.) for the feeder and outage reason and subreason combination, UGLF is
the length of the feeder that is to be undergrounded, and Do is the average outage
duration (hrs.) for the outage reason and subreason combination. MEo, RF,o, and Do were
calculated as part of the outage benefit analysis and shown in Table 2 and Table 3.
The results of the failures and outages direct cost analysis are shown in Table 6 and Figure 6.
Table 6 shows an example of the calculation for one feeder, and Figure 7 shows the distribution
of the mitigated direct cost for 195 feeders with proposed undergrounding.
Table 6. Example Mitigated Annual Direct Cost Calculation for a Feeder
Feeder Outage Reason: MEo RF,o UGLF Do STR Mitigated ADCostF
Name Subreason (outages/ (mi.) (hrs.) ($/hr.)
yr./mi.)
9CE12F4 ANIMAL:Bird 1 0.01816 2.18 1.69 $1,077.49 $72.20
9CE12F4 ANIMAL:Other 1 0.00327 2.18 1.88 $1,077.49 $14.42
9CE12F4 ANIMAL:Protected 1 0.00018 2.18 1.60 $1,077.49 $0.68
9CE12F4 ANIMAL:Squirrel 1 0.03632 2.18 1.46 $1,077.49 $124.18
9CE12F4 COMPANY:Other 0.5 0.01059 2.18 1.39 $1,077.49 $17.23
9CE12F4 EQUIPMENT OR 0 2.18 2.05 $1,077.49 $0.00
Arrester 0.8
9CE12F4 EQUIPMENT OR 0.00018 2.18 2.38 $1,077.49 $0.80
Capacitor 0.8
9CE12F4 EQUIPMENT OR 0.01047 2.18 3.24 $1,077.49 $63.65
Conductor-Pri 0.8
9CE12F4 EQUIPMENT OR 0.03632 2.18 2.01 $1,077.49 $136.98
Conductor-Sec 0.8
9CE12F4 EQUIPMENT OR 0 2.18 2.61 $1,077.49 $0.00
Connector-Pri 0.8
9CE12F4 EQUIPMENT OR 0.00828 2.18 1.82 $1,077.49 $28.24
Connector-Sec 0.8
9CE12F4 EQUIPMENT OR 0.00164 2.18 3.15 $1,077.49 $12.09
Crossarm-rotten 1
9CE12F4 EQUIPMENT OR 0 2.18 2.29 $1,077.49 $0.00
Cutout/Fuse 1
Page 22 2407043.000-9196 t. V'TM

October 30, 2024
Feeder Outage Reason: ME, RF,,, UGLF Do STR Mitigated ADCostF
Name Subreason (outages/ (mi.) (hrs.) ($/hr.)
yr./mi.)
9CE12F4 EQUIPMENT OH: 0.00247 2.18 2.92 $1,077.49 $13.55
Insulator 0.8
9CE12F4 EQUIPMENT OH: 0.00142 2.18 2.86 $1,077.49 $9.52
Insulator Pin 1
9CE12F4 EQUIPMENT OH: 0 5 0.00373 2.18 2.30 $1,077.49 $10.08
Oer9CE12F4 EQUIPMENT OH: 0.00112 2.18 4.59 $1,077.49 $12.03
Pole-rotten 1
9CE12F4 EQUIPMENT OH: 0.00030 2.18 2.38 $1,077.49 $1.68
Recloser 1
9CE12F4 EQUIPMENT OH: 0.00020 2.18 2.60 $1,077.49 $0.73
Regulator 0.6
9CE12F4 EQUIPMENT OH: 0.00040 2.18 1.40 $1,077.49 $0.52
Switch/Disconnect 0.4
9CE12F4 EQUIPMENT OH: 0 2.18 3.88 $1,077.49 $0.00
Transformer-OH 0.5
9CE12F4 EQUIPMENT OH: 0.00002 2.18 4.39 $1,077.49 $0.21
Wildlife Guard 1
9CE12F4 MISCELLANEOUS: 0.00114 2.18 2.38 $1,077.49 $0.00
SEE REMARKS 0
9CE12F4 POLE FIRE:Pole Fire 1 0.00890 2.18 4.47 $1,077.49 $93.33
9CE12F4 PUBLIC:Car Hit Pole 1 0.05447 2.18 3.03 $1,077.49 $387.16
9CE12F4 PUBLIC:Fire 0 0.07263 2.18 1.54 $1,077.49 $0.00
9CE12F4 PUBLIC:Other 0.8 0.03632 2.18 1.82 $1,077.49 $124.10
9CE12F4 PUBLIC:Tree 1 0.00403 2.18 2.87 $1,077.49 $27.12
9CE12F4 TREE:Service 1 0.01816 2.18 2.05 $1,077.49 $87.27
9CE12F4 TREE:Tree Fell 1 0.01816 2.18 3.15 $1,077.49 $134.45
9CE12F4 TREE:Tree Growth 1 0 2.18 1.93 $1,077.49 $0.00
9CE12F4 TREE:Weather 1 0 2.18 5.63 $1,077.49 $0.00
9CE12F4 UNDETERMINED: 0.07263 2.18 2.10 $1,077.49 $325.34
Undetermined 0.91
9CE12F4 WEATHER: Heat 0 0.00004 2.18 7.96 $1,077.49 $0.00
9CE12F4 WEATHER: Lightning 0.8 0.01816 2.18 3.99 $1,077.49 $136.11
9CE12F4 WEATHER:Snow/Ice 1 0.05447 2.18 10.29 $1,077.49 $1,315.63
9CE12F4 WEATHER:Wildfire 0.5 0.00030 2.18 9.57 $1,077.49 $3.36
9CE12F4 WEATHER:Wind 1 0.10895 2.18 17.22 $1,077.49 $4,405.51
Feeder Total $7,558.15
r1
Page 23 2407043.000-9196 �TM

October 30, 2024
35
30
25
i
20
E 15
Z
10
5
0
1 1 1 1 1 1 1 dtl IIT� N�M L F1 F1
OK 50K 100K 150K 200K 250K 300K 350K 400K
Mitigated Direct Cost($)/Year
Figure 6. Distribution of mitigated direct costs per year for
195 feeders with proposed undergrounding.
Operations and Maintenance
Exponent calculated the change in Operations and Maintenance ("O&M") costs associated with
each undergrounding project associated with vegetation management and other O&M costs.
Vegetation Management
Avista provided Exponent with vegetation management costs for each feeder from January 2020
to August 2024 (4.67 years), which we understand does not include administrative costs
(representing around 10% of the total cost for vegetation management). We understand that
Avista's vegetation management program runs on a 5-year cycle, in addition to yearly spend,
thus the data does not quite represent a full cycle of costs. Lacking further information, Exponent
proceeded on the basis that the available data is approximately representative of the costs for
vegetation management for each feeder.
To determine the change in costs for vegetation management stemming from the underground
projects, Exponent performed the following steps:
1. The average cost per year is calculated for each feeder. The value is divided by
0.9 to include administrative costs.
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Page 24 2407043.000-9196 ��

October 30, 2024
2. The average cost per year per mile for each feeder is calculated by dividing the
average cost per year for a feeder by the length of the feeder.
3. For feeders without vegetation management cost data, it is assumed that cost per
year per mile is equal to the overall average cost per year per mile across all
feeders (considering that feeders have different lengths). Figure 7 shows a
histogram of the cost per mile per year for vegetation management for each
feeder. The average is around $1,900/year/mile.
4. It is assumed that undergrounding is 100% effective at reducing vegetation
management costs.
5. The annual benefit associated with vegetation management, for a feeder, is
calculated as the vegetation management cost per mile per year multiplied by the
length of the feeder that is to be undergrounded, multiplied by the mitigation
effectiveness of undergrounding for vegetation management(100%).
300
250 243
200
LA
a,
tea, 150
a)
U
100
50
32
0
QQQ� QQQ� QQQ� QQQ� QQQ� QQQ� QQQ� QQQ
�Y''l QQQ N \QQQ QQQ OO OO OO
(ONQ Q Q
Average Cost/Year/Mile
Figure 7. Histogram of vegetation management costs per year per mile for each feeder.
Page 25 2407043.000-9196 t x TM

October 30, 2024
Other O&M
Avista provided Exponent with O&M costs from 2019 through 2023 (5 years), omitting
vegetation management costs, for both their current approximately 7,700 line miles of overhead
feeder(approximately $67 million) and approximately 5,000 line miles of underground feeder
(approximately $3.8 million). Costs were not apportioned to feeders. The change in O&M costs
(non-vegetation management) is determined as follows:
1. The O&M cost per year per mile for both overhead and underground is calculated
on a system-wide basis. The average cost per year per mile for overhead is
approximately $1,700, and the average cost per year per mile for underground is
approximately $150. The large difference in yearly O&M costs per mile is likely
because the underground sections are newer than the overhead sections. This bias
will continue to exist, however, as underground sections replace overhead
sections.
2. The change in yearly cost for a feeder when undergrounding is implemented is
calculated by multiplying the length of the undergrounding segment by the
difference in yearly cost per mile between underground and overhead sections.
Wildfire Losses
The purpose of this analysis is to determine the benefit due to reduced losses from Avista-caused
wildfires, in terms of dollars, associated with undergrounding different feeders. Losses
associated with wildfires are typically expressed in terms of dollars, consisting of contributions
from deaths, structures burned, and acres burned. To date, Avista has not conducted analyses to
determine the expected deaths, structures burned, and acres burned for fires started at various
points in their system, or studies of the probability of ignitions occurring at various points in
their system.
However, Avista has performed a relative risk analysis of the consequences of ignitions
occurring at different locations on their system and spreading 3 miles in every direction from
different locations on their system, each identified by a hex (Figure 8). That analysis considers
local conditions such as vegetation, structure density, and population density. Relative risk
scores are expressed in terms of ratio to the average consequence of all hexes in Avista's system.
These risk scores are calculated for hexes along Avista's entire system. Each hex also contains a
percentage of the area that is treed.
Page 26 2407043.000-9196 t x TM

October 30, 2024
Hex for Proposed UG
Hex for Current OH and UG J_
— Proposed UG
— Current OH
R
Current UG
H
d s
Figure 8. Example Hexes from Avista's Consequence Analysis.
In the absence of Avista-specific consequence data that can be translated into dollars, and the
associated probabilities, Exponent has developed a methodology that leverages data from
FEMA's National Risk Index' to determine reductions in losses associated with Avista-caused
wildfires when undergrounding is implemented on selected feeders.
FEMA's National Risk Index estimates the risk due to a variety of natural hazards, including
wildfires. That risk is expressed in terms of Expected Annual Loss (EAL), considering building
value, population, and agricultural value. The EAL is in units of dollars of loss per year
associated with a particular hazard in a particular census tract. FEMA calculates the EAL using
an equation that combines values for exposure, annualized frequency, and historical loss ratios
for each of 18 hazard types. EALs are calculated for each census tract level in the United States.
Exponent has used the EAL for wildfire as a basis for calculating financial losses associated with
Avista-caused wildfires.
The FEMA EAL's for wildfire include losses associated with both utility-caused and non-utility-
caused wildfires. While there is no definitive information regarding the proportion of wildfire
' https:Hhazards.fema.gov/nri/map
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October 30, 2024
losses that are from utility-caused wildfires, an auditor's report2 in California estimated that 19%
of acres burned in California between 2016 and 2020 were from electric utility-caused wildfires
(Figure 9). On that basis, Exponent has assumed that 19% of the EAL from FEMA's NRI data
can be attributed to electric utility-caused wildfires. It must be recognized that there is
uncertainty associated with this value and there is likely to be significant fluctuation from year to
year and region to region.
WILDFIRES WILDFIRES CAUSED BY ELECTRICAL POWER
MACRISBURNED
2016 2,816 245,000 270 10% 3,000 1%
2017 3,470 467,000 408 12 250,000 54
2018 3,504 1,063,000 297 8 247,000 23
2019 3,086 130,000 304 10 84,000 65
2020 3501 1,459,000 335 10 59,000 4
Totals 16,377 3,364,000 1,614 10% 643,000 19%
Source: Cal Fire's Wildfire Activity Statistics reports,2016 through 2020.
Note: These data consist primarily of wildfire incidents within the Cal Fire direct protection area responded to by Cal Fire personnel.
Figure 9. Proportion of wildfires and acres burned in California caused by electric power
from 2016 to 2020.
The EAL from census tracts must also be apportioned to specific feeders being considered for
undergrounding. The procedure to determine how to apportion the EAL from a census tract to a
feeder is as follows:
1. The expected annual loss due to wildfires in the census tract, from FEMA's NRI, is
termed EALi, where i indicates the census tract.
2. The proportion of losses within the census tract that are attributed to electric utility-
caused wildfires is termed PU, and is assumed to be 0.19.
3. The proportion of the census tract that is in Avista service territory is calculated via a GIS
overlay of Avista's service territory with a GIS map of the census tracts. The variable is
termed PA1. This recognizes that a census tract may contain multiple electric utility
operators, all of whom likely contribute to the wildfire risk. As specific information is not
known about the consequences of wildfires caused by other utilities, a simplifying
assumption was made that the losses attributed to Avista would be based on the
proportion of the census tract that is Avista service territory.
4. As there can be multiple feeders within a census tract, and only portions of feeders are
typically undergrounded, the wildfire losses must be apportioned to each hex within the
census tract. This is done by calculating a weighting factor, WFh, for each hex within the
2 California State Auditor Report 2021-117
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October 30, 2024
census tract. The weighting factor each hex is based on a combination of the risk score
for the hex, RSh, and a proxy for the probability of ignition based on a combination of the
average wood pole failure rate within the hex and an estimate of the tree failures in the
hex. The average wood pole failure rate within the hex is expressed as, 1.f,h, and its
calculation is described in the next section. In the absence of more precise data on tree-
induced ignitions, the tree failure rate, tf,h, is estimated as the ratio of tree-induced
outages on the feeder to wind outages on the feeder multiplied by the A1f,h, and then
multiplied by the ratio of the percentage of the hex that is treed to the average percentage
treed of all hexes on the feeder. It is recognized that this is not an actual tree-induced
ignition rate but is merely a mechanism for considering the likelihood of tree-induced
ignitions relative to wood pole failure-induced ignitions.
_ tree outage on feeder % Treed in Hex
tf,h wind outages on feeder X �f'h X Avg. % Treed on Feeder
5. The weighting factor for the hex is calculated by multiplying the risk score for the hex by
the sum of the average wood pole failure rate and the estimated tree failure rate.
WFh = [A.f,h + tf,h] X RSh
An emphasis is placed on tree and pole failure as these tend to occur in windier
conditions, and dry, windy conditions are conducive to wildfire ignitions in general and
larger wildfires in particular. Weighting factors are determined in this way for each hex
within the census tract.
6. It is assumed that if a section of a feeder has been undergrounded, the contribution to the
wildfire losses is zero, as it is highly unlikely that there will be a large wildfire caused by
an undergrounded segment.
7. Within a census tract, losses are apportioned to the section of a particular feeder that is a
candidate to be undergrounded by summing the weighting factors for all hexer on that
feeder within the census tract that are in sections to be undergrounded and dividing by the
sum of the weighting factors for all hexes within the census tract. As losses are being
determined on a feeder-by-feeder basis, the weighting factor for each hex must also be
weighted by the proportion of the hex that belongs to the particular feeder, PFh. This
value is typically 1; however, some hexes contain multiple feeders. This apportionment
factor is termed, PMf,i.
PMf, ZUG zone WFh X PFh
i =
census tract i WFh
If the entirety of Avista's lines within a census tract were to be undergrounded, the sum
of PMf,i for all feeders in the census tract would be equal to 1.
8. It is assumed that wildfire losses associated with any sections to be undergrounded are
100%mitigated by the undergrounding.
, TM
Page 29 2407043.000-9196 t

October 30, 2024
9. The expected annual mitigated losses due to Avista-caused wildfires for a feeder,
EALf,,,,, are calculated by summing, for all census tracts that contain the feeder, the
apportionment factor for the feeder in the census tract multiplied by the EAL for the
census tract and the proportion of the census tract that is Avista service territory, and
multiplying that summation by the proportion of losses that are assumed to be caused by
electric utilities.
EAL f,m = PU PMf,iEALIPAi
all census tracts,i,
containing feeder,f
10. This process is repeated to determine the mitigated wildfire losses for all feeders that
Avista has identified as candidates for undergrounding.
Wood Poles Failure Rates
Overview of Methodology
As part of Exponent's evaluation of losses associated with wildfires, Exponent used average pole
failure rates within hexes to weight hexes for apportioning losses from census tract data. This
section details the methodology used to estimate failure rates for individual wood poles.
The following data was available for individual wood poles:3
- Pole class
- Pole location (latitude/longitude)
- Installation date and/or year manufactured
- Pole top condition qualitative ranking (Do nothing, needs further review, replace
pole)
- Shell rot condition qualitative ranking (New, good, fair, bad, immediate attention
required)
- Remaining strength (as a percentage of new pole strength)
- Cross arm condition qualitative ranking (New, good, fair,bad, immediate
attention required)
Exponent performed a quantitative risk analysis ("QRA")to determine the annual failure rate of
each wood pole. The concept within QRA is that vulnerability is determined numerically based
on data and via mathematical and scientific analysis. This method is in contrast to qualitative risk
analysis, whereby the relative risk of components is determined by expert opinion and
3 Some poles do not have all these data field populated.
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October 30, 2024
experience without the same mathematical rigor. Exponent has used a methodology called
Performance-Based Engineering ("PBE") to perform this assessment.
As part of this methodology, the concepts of hazard curves and fragility curves play pivotal roles
in quantifying the relationship between the hazard intensity and the vulnerability of different
components. The hazard curve illustrates the rate of exceeding a given level of load intensity,
e.g., the frequency that the 3-second wind gust is expected to exceed a certain speed. The
fragility curve defines the likelihood of exceeding some predefined damage state (i.e.,failure) at
a corresponding hazard intensity, e.g., the probability of wood pole failure given a-second wind
gust speed. Sample hazard and fragility curves for wind are shown in Figure 10.
The hazard and fragility functions can be combined to calculate the annual rate, /., at which the
unwanted outcomes are expected to occur(i.e., the frequency of failures, or failure rate, for
short). In this report, Exponent refers to this integration as the Probability Framework Equation.
For low exceedance frequencies, the annual rate approximates the annual probability of failure.
The annual exceedance frequency, annual failure rate, and annual probability of failure are often
used synonymously in this context and, while not exactly the same, are normally very close for
practical ranges of failure probabilities. The Probability Framework Equation is:
00
A = f P(f Jim) I d dh dim
0
Where p(f I im) is the probability of an outcome f conditioned on the intensity of the hazard im,
dh
dim I is the absolute value of the derivative of the hazard curve (i.e., the slope of the hazard
curve), and the integration is performed over all possible intensities of hazards. In other words,
the Probability Framework Equation is the integration of the fragility curve with the derivative of
the hazard curve.
Page 31 2407043.000-9196 t x TM

October 30, 2024
1.00E+03 \ 1
c 1.00E+01 0.9
f6 0.8
v 1.00E-01 y
u 0.7
x —
w 1.00E-03 - 0.6
LL
o w
0
u 1.00E-05 >0.5
C Y
d —
Q 1.00E-07 10 0'4
v a
ti 2 0.3
1.00E-09 a
0.2
c
Q 1.00E-11 0.1
1.00E-13 0
0 20 40 60 80 100 120 0 20 40 60 80 100 120 140
3-Second Gust Windspeed[m/s] 3-Second Gust Windspeed[m/s]
Figure 10. Sample hazard curve (left) and fragility curve (right).
Hazard Curves
Hazard data was acquired from the Applied Technology Council's hazard tool,'which yields
wind speeds corresponding to mean recurrence intervals ("MRI", also referred to as "return
periods") for 10, 25, 50, 100, 300, 700, 1700, and 3000 years. American Society of Civil
Engineers ("ASCE")hazard tools shows contour maps for certain recurrence intervals,
reproduced for 300-year and 700-year wind speeds in Figure 11 and Figure 12, respectively. It is
seen that there is no significant variation in wind speeds corresponding to a particular MRI in
Eastern Washington and Western Idaho (i.e., Avista's service territory). There is some,but not
significant, variation in wind hazard curves across Avista's service territory. Exponent therefore
acquired baseline wind speed MRIs for several sites spaced out geographically within Avista's
service territory using the available hazard tools, and then interpolated to determine the MRI
parameters at the location of each individual pole. Finally, for each pole, a Gumbel hazard curve,
using the below equation, was fit to the wind speed MRI data.
1
h(im) — ( M-loc
1 — e-e scale
Where h is the probability of exceedance of 3-second gust speed, im, and loc and scale are the
location and scale parameters of the Gumbel distribution, respectively. Figure 13 shows an
example hazard curve fit to MRI wind speed data.
4 https:Hhazards.atcouncil.org/
s https:Hascehazardtool.org/
Page 32 2407043.000-9196 t, l M

October 30, 2024
' y0'H pan w
b 'P
J'A
2 d
Figure 11. Contours from ASCE Hazard Tool for 300-
year wind speed.
,A
Figure 12. Contours from ASCE Hazard Tool for 700-
year wind speed.
Page 33 2407043.000-9196 7 � TM

October 30, 2024
100
>, 10-1
c�
0
L
10 2
U
(B
N
U
x 10-3
w
c
c
Q 104
0 20 40 60 80 100 120 140
3-Second Wind Gust Speed [mph]
Figure 13. Example wind speed hazard curve and underlying MRI data.
Fragility Curves
Baseline (notional) new pole fragility curve
Fragility curves are typically defined by lognormal cumulative distribution functions with
median, µ, and dispersion, f3, parameters:
p(f d im) = 1 2 1 + erf(In im im fl — µ
Where im is the value of the intensity measure, e.g., 3-second wind gust speed, and p(f I im) is
the probability of failure of the asset at that value of im. The median corresponds to the wind
speed at which half of poles would fail. The dispersion parameter will be lower when there is
less uncertainty in the strength of the pole, and higher when there is more uncertainty
surrounding the strength of the pole. For example, all else being equal, strength estimates for an
older pole will be less certain due to an uncertain rate of degradation, thus reflected in a higher
dispersion parameter. Higher dispersion reduces the steepness of the fragility curve.
Page 34 2407043.000-9196 t'x TM

October 30, 2024
Either decreased capacity or increased uncertainty(dispersion) will cause the probability of
failure in practical ranges of hazard intensity to increase, thereby increasing the calculated
vulnerability associated with that asset. For instance, wood poles can decay over time, thus
reducing their structural capacity. However, we lose confidence in a wood pole's capacity to
resist wind as the pole approaches the end of its design life, even if it is in visually good
condition. Strength reduction shifts the bell curve model of capacity to the left, and increased
uncertainty (higher standard deviation) causes it to fatten. As an example, consider the results of
strength tests of new and existing poles conducted by the Electric Power Research Institute
(Figure 14). The strength distribution of older wood poles has shifted the bell curve to the left,
while increased variability(uncertainty) is illustrated by the fattening of the curve.
—poles of average age 30 years —new poles
T
C
W
7
W
I
I I
I
0 3,000 6,000 9,000 12,000 15,000
Groundline Strength(psi)
Figure 14. Loss of strength and increased dispersion as wood poles age (from EPRI, 1986).
Fragility curves can be estimated through detailed engineering analysis, experimentation, review
of historical data, or, in the absence of information, expert consensus. It is expected that the
fragility curve will be different for poles of different classes or ages. Wood poles are designed
(or classed)based on environmental loads from wind, ice, or wind concurrent with ice accretion.
In addition,wood poles are most often replaced or strengthened because their capacity to resist
wind has degraded such that they can no longer bear loads prescribed by design standards.
Estimating the fragility function median strength parameter for each individual overhead
structure asset would require either knowing the loads to which it was designed or performing
sag-tension calculations, both of which would require substantial research and/or calculation. For
the purposes of this study,which is aimed at providing approximate estimates of failure rates for
the purposes of apportioning wildfire losses between hexes, Exponent estimates a fragility curve
TM
Page 35 2407043.000-9196 ��

October 30, 2024
for each wood pole as if it were a new asset (notional fragility) based on failure rates described in
the technical literature. The fragilities are then adjusted based on the wind hazard curve at
individual poles and based on the pole's remaining strength, shell rot condition code, or age.
The median strength used for the notional fragilities of wood poles has been informed by
reliability-based design targets provided by publicly available technical literature. One such
document is Reliability-Based Design of Transmission Line Structures: Final Report, Publication
EL-4793 by the Electric Power Research Institute. Based on calibration studies, the document
provides a range of target reliability indices ranging from 2.7 to 3.2. Similarly, Reliability-based
Design of Utility Pole Structures, a 2006 publication by the American Society of Civil
Engineers, suggests an annual failure rate of 0.00046 (based on a 50-year reliability index of 2.0)
for existing wood poles. Based on engineering judgement, this lower reliability index(2.0) is
adopted for the notional new wood pole fragility curve, recognizing that it is intended for poles
that have been in service because a) in our experience, wood poles fail more frequently than steel
structures, even when in almost new condition, and b)the potential for under-build, which can
increase the wind load beyond the design intent.
Specifically, the new pole dispersion parameter is estimated to be 0.3, based on engineering
judgement, and the new pole median at a particular location, is back-calculated from the
Probability Framework Equation. Every pole, when new, will thus have the same initial failure
rate (and dispersion), but varying median because of the different hazard curves at each site.
Modifying fragility curve to account for condition
The notional fragility curve for each pole is modified to account for observational data and the
age of the pole. The hierarchy for modification is as follows:
1. Where pole remaining strength data is provided, the new pole strength is
multiplied by the remaining strength parameter, RS, which can theoretically range
from 0 to 100%. Because the wood pole fragility curves relate wind speed to the
probability of failure, and wind force is proportional to wind speed squared, the
modification to the median of the fragility curve is modified as follows:
Padjusted — Ynew RS
2. Where pole remaining strength data is not provided, but the shell rot condition
code is provided, the remaining strength is estimated based on the condition code.
Shell rot condition code is used for this purpose instead of pole top condition code
because the shell rot condition code is a better proxy for the likelihood of
groundline failure due to wind loading. Review of the relationship between
remaining strength data, where provided, and the shell rot condition code of the
same pole did not reveal a consistent trend. Thus, the mapping of shell rot
condition code to assumed remaining strength assumes that poles with a condition
code of"new"will have a remaining strength of 1, and poles classified as
Page 36 2407043.000-9196 Fx TM

October 30, 2024
"immediate attention required"will have a remaining strength of 0.67.E The
remaining strength corresponding to "good," "fair," and"bad" are interpolated
between the "new" and "immediate attention required"remaining strength values,
as indicated in Table 7.
Table 7. Assumed remaining strength for different shell rot conditions.
Shell Rot Condition Code Remaining Strength Parameter
New 1
Good 0.9175
Fair 0.835
Bad 0.7525
Immediate Attention Required 0.67
3. Where a pole does not have a remaining strength value or a shell rot condition
code, the age of the pole is used to estimate the remaining strength. Figure 15
shows a histogram of pole ages for each shell rot condition code. As expected,
poles with condition code "new" are mostly young (between 0 and 15 years old),
and as the condition code progresses to good, fair, bad, and immediate attention
required, the typical ages increases. It is notable that a number of young poles
have lower condition codes,potentially due to infant mortality. Based on a review
of the data, a mapping between age, and remaining strength, shown in Table 8 and
plotted in Figure 16, was developed and is used where only age information is
available about a pole.
6 This aligns with guidance in California's G.O.95 that poles must be replaced when they have lost one third of
their original strength.
TM
Page 37 2407043.000-9196 ��

October 30, 2024
3500 Histograms of Ages by SHELLROT DESCRIPTION
0 BAD
0 FAIR
3000 0 GOOD
OIMMEDIATE ATTENTION REQUIRED
ONEW
2500
2000
c
0
U 1500
1000
500
0 Loll.. . . . . . =�f=L F !
0 20 40 60 80 100 120
Age
Figure 15. Histogram of wood pole ages for each shell rot condition code.
Table 8. Mapping of Age to Remaining Strength
Age Range Remaining Strength
0to7years 1
7 to 31 years 1 — (age — 7) (1 —0.9175)
31 - 7
31 to50years 0.9175 — (age —31) 0.9175 — 0.835( 50 - 31 )
0.9175 — 0.835
> 50 years 0.835 — (age— 50)( 50 — 31 )
, TM
Page 38 2407043.000-9196 t

October 30, 2024
1
0.9
m
0.8
m
E 0.7
CU
M
0.6
a)
0.5
L
ll+^�
vJ
o) 0.4
E 0.3
a)
Of 0.2
0.1
0
0 20 40 60 80 100
Age [years]
Figure 16. Estimate of Remaining Strength as a function of age; used in the absence of
shell rot condition code or explicit measurement of remaining strength.
The dispersion parameter, (3, is also assumed to be age-dependent, to account for the fact that
there is more certainty in new wood pole strength than in older wood pole strength. The steps to
determine the age-dependent value of/3 are as follows:
1. The new pole dispersion value is termed/lo and is assumed to be equal to 0.3.
2. The new-pole fragility curve median, µn,e, is back-calculated based on(lo, and
assumed new pole failure rate discussed previously, and the hazard curve for the
site.
3. The fragility curve median at the end of life, µEOL, is assumed to be 2/3 of the
new pole median.
4. The failure rate at the end of life, AEOL, is estimated using the Probability
Framework Equation with the hazard curve for the site, µEOL, and(3o.
5. An intermediate dispersion value, /30, is back-calculated using the hazard curve
for the site, AEOL, and µnew
6. A rate of change parameter, p, between the new pole dispersion, flo, and the
maximum dispersion, is calculated as follows, assuming the maximum
Page 39 2407043.000-9196 t x TM

October 30, 2024
value the dispersion parameter will ever take (extremely old pole) is l3r„ax = 0.5,
C = 0.2, and the Design Life of the pole is 80 years.
In (F'max — flo)
_ C
P Design Lide
7. The value of/3 at any age is calculated as follows:
ll(age) _ fl .ax — C - eP age
Figure 17 shows the dispersion value for a wood pole of various ages ranging between 0 and 150
years at an example location.
0.42
0.4
0.38
0.36
0.34
0.32
0.3
0 50 100 150
Age [years]
Figure 17. Example relationship between pole age and fragility curve dispersion parameter,
Page 40 2407043.000-9196 t. V'TM

October 30, 2024
Calculated Wood Pole Failure Rates
Figure 18 shows a histogram of estimated pole annual failure rates.
x 104
5
4.5
4
3.5
3
c
0 2.5
U
2
1.5
1
0.5
0 0.02 0.04 0.06 0.08 0.1
Annual Failure Rate
Figure 18. Histogram of estimated wood pole annual failure rates.
Calculating Benefit-Cost Ratios
Benefit-cost ratios are calculated for individual feeders based on the cost of undergrounding
sections of that feeder and the calculated benefits associated with undergrounding. The benefits
are calculated for the current system configuration. It is unknown when each project will be
undertaken, and information is not available on vulnerabilities in future years, e.g., changing
wildfire consequences, thus all analysis is performed as if the project will be undertaken
immediately, and that benefits are the same in the future year as in the current year(adjusted for
the time-value of money, using the discount rate).
The annual benefit in year zero for feeder i, Bi,o, is calculated as the sum of benefits from the
various analysis components for that feeder:
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October 30, 2024
Bi,o = 0&M (non — veg.) + 0&M(veg) + Outage Customer Impact + Outage Repair
+ Wildfire
In future year y, measured from today, the annual benefit for feeder i, Bi,y, considering the
discount rate, d, is calculated as:
_ Bi,O
B`'y (1 + d)y
The benefit-cost ratio for each feeder, BCRi, is calculated as follows:
n
BCRi = y=1 Bi'y
Ci
Where Ci is the cost of the undergrounding project on feeder i, assumed to be incurred
immediately and n is the expected useful life of the underground segment. Avista estimates that
the expected useful life of the undergrounding projects is 98 years, while the economic book life
is 55 years. Exponent has therefore used the average value of 76.5 years in calculations of benefit
cost ratios.
It is common to assume two different values of the discount rate in public projects:
• 7%: which considers the market rate of return on capital
• 3%: which considers the rate of return on capital after taxes
Avista has used a value of 6.89%when calculating benefit cost ratios for other projects, thus, for
consistency, Exponent has adopted that value for this study. It is noteworthy that a lower value
will result in higher benefit-cost ratios.
Page 42 2407043.000-9196 t x TM

October 30, 2024
Costs of Undergrounding
To determine the benefit to cost ratio of proposed undergrounding projects, Avista provided the
estimated cost to underground 2,074.3 miles of OH distribution lines over 177 feeders. The cost
per feeder is estimated using 5 categories:
1. fixed costs, which consider project labor,
2. civil construction costs, which consider excavation and conduit installation work,
3. trunk and lateral build costs, which consider cable installation,pad mount
transformers, and service riser installation,
4. distribution automation costs, which consider equipment installation to transition
from underground to overhead lines, and
5. service transfer and overhead wreckout costs, which consider the removal of the
existing overhead infrastructure and maintaining power supply during
construction.
For each feeder, the costs are summed across all categories. Figure 19 shows the distribution of
the estimated costs of undergrounding projects for 177 feeders.
40
35
i 30
a�
25
LL
6 20
L
15
Z 10
0
N � l0 00 O N V 0 00 O N V t0 00 O N � W 00 O N � W 00
to to to to -I -I i rl e-I N N N N N m m m m m V V 1* 1:T -1
N t/1 t/1 Vl t/1• t/1• t/? t/? th V1 t/� t/1• t/? V} t/� t/1• t/? V? -Ln to
O rq ZT t0
00 O N � W 00 O N t0 00 O N 0 CO O N � 0
-I N N N N N m m m m m 4 -4 Tr Ic:T
Estimated Cost ($)to Underground
Figure 19. Distribution of the estimated cost to underground for 177 feeders.
Page 43 2407043.000-9196 7 IX TM

October 30, 2024
Cost-Benefit Analysis Results
In the cost-benefit analysis, the estimated cost of undergrounding projects was compared to the
benefits of completing the undergrounding projects for each feeder. Table 9 shows the results of
the cost-benefit analysis. The benefit-cost ratio ("BCR") evaluates whether the benefits outweigh
the project cost for each feeder. A higher BCR indicates a feeder that derives more benefit per
dollar spent. A BCR greater than 1 indicates that the benefits exceed the costs, suggesting that
the undergrounding project on that feeder is financially advisable. Conversely, a BCR less than 1
indicates that the costs exceed the benefits, suggesting that the undergrounding project on that
feeder is not financially advisable. The BCR can thus be used to prioritize investments, ensuring
that resources are allocated to undergrounding projects with the greatest potential for positive
returns.
Table 9. Cost-Benefit Analysis Results by Feeder
Feeder O&M O&M Veg. Outage Repair Wildfire Total Benefit Cost ($) Benefit-
Name Reduction Management Reduction Reduction Reduction ($)over the of Under- Cost Ratio
Benefit Reduction Benefit Benefit Benefit time horizon grounding (BCR)
($/yr.) Benefit($/yr.) ($/yr.) ($/yr.) ($/yr.) of 76.5 years Project
9CE12F4 $3,454 $13,606 $55,135 $7,558 $492 $1,237,048 $873,177 1.42
9CE12F6 $3,669 $2,900 $403,078 $30,176 $246 $6,783,990 $3,304,405 2.05
AIR12F1 $57,599 $23,400 $479,026 $57,647 $62,140 $10,479,806 $33,075,636 0.32
AIR12F2 $7,712 $2,860 $142,532 $10,953 $3,871 $2,588,735 $6,144,234 0.42
AIR12F3 $7,669 $7,047 $14,247 $9,593 $4,537 $664,321 $10,076,103 0.07
APW112 $2,871 $4,153 $447,864 $14,635 $44 $7,238,714 $1,686,068 4.29
APW113 $5,836 $4,004 $276,652 $34,088 $1,237 $4,961,044 $1,981,731 2.50
ARD12F2 $15,958 $13,559 $218,822 $32,900 $1,689 $4,361,553 $3,221,763 1.35
AVD151 $28,172 $64,533 $3,034,252 $169,664 $2,101 $50,852,194 $19,671,802 2.59
AVD152 $1,807 $1,559 $126,654 $8,499 $2 $2,135,405 $2,291,407 0.93
BEA12F2 $3,830 $5,119 $300,665 $14,601 $57 $4,998,899 $1,636,467 3.05
BIG411 $12,774 $77,088 $281,559 $33,007 $397 $6,240,681 $11,133,726 0.56
BIG412 $3,530 $9,376 $36,074 $17,060 $58 $1,018,948 $2,085,508 0.49
BIG413 $3,416 $3,480 $515 $7,588 $76 $232,393 $4,763,644 0.05
BKR12F2 $3,495 $4,198 $5,036 $2,591 NaN $236,173 $4,031,713 0.061
BKR12F3 $3,379 $353 $44,453 $5,966 $11 $834,958 $2,025,847 0.41
BLA311 $38,573 $75,535 $371,377 $102,053 $598 $9,066,533 $11,351,137 0.80
BLD12F4 $18,739 $43,623 $572,250 $43,516 $0 $10,453,847 $10,338,295 1.01
BLD12F6 $854 $1,026 $30 $2,225 $0 $63,755 $0 NaN,
BLU321 $23,687 $60,056 $1,844,599 $114,412 $167 $31,493,107 $8,652,279 3.64
BLU322 $30,044 $55,508 $1,682,018 $254,002 $355 $31,169,493 $12,228,115 2.55
BUN424 $5,313 $48,066 $4,718 $17,976 $99 $1,174,250 $7,596,558 0.15
BUN426 $3,691 $5,213 $47,514 $10,580 NaN $1,032,826 $1,910,005 0.541
CDA123 $7,914 $23,490 $1,824,890 $84,946 $443 $29,932,444 $2,684,363 11.15
CDA125 $1,981 $5,214 $437,060 $16,051 $22 $7,096,301 $770,927 9.20
CFD1210 $13,995 $7,862 $179,476 $16,850 $21,017 $3,687,458 $7,348,476 0.50
CFD1211 $17,384 $8,257 $102,640 $13,445 $53,755 $3,013,483 $12,187,942 0.25
CHE12F4 $16,029 $16,491 $785,667 $71,137 $3,405 $13,762,067 $9,281,687 1.48
CHW12F2 $33,576 $55,399 $503,802 $65,872 $24,157 $10,525,932 $15,339,288 0.69
CHW12F3 $30,810 $30,576 $351,995 $69,502 $5,733 $7,532,370 $13,278,795 0.57
Page 44 2407043.000-9196 t'x TM

October 30, 2024
Feeder O&M O&M Veg. Outage Repair Wildfire Total Benefit Cost ($) Benefit-
Name Reduction Management Reduction Reduction Reduction ($)over the of Under- Cost Ratio
Benefit Reduction Benefit Benefit Benefit time horizon grounding (BCR)
($/yr.) Benefit($/yr.) ($/yr.) ($/yr.) ($/yr.) of 76.5 years Project
CHW12F4 $18,445 $27,697 $189,421 $48,013 $9,627 $4,519,944 $5,008,289 0.90
CKF711 $28,732 $66,759 $709,951 $77,506 $8,957 $13,749,366 $8,466,977 1.62
CKF712 $9,477 $8,106 $261,854 $39,378 $2,171 $4,948,241 $1,926,087 2.57
CLA56 $12,856 $6,896 NaN $8,397 NaN $433,934 $5,458,364 0.08b
CLV12F2 $34,332 $56,346 $722,493 $68,908 $27,402 $14,020,315 $13,442,572 1.04
CLV12F4 $32,141 $52,268 $769,595 $75,221 $17,840 $14,599,679 $11,457,505 1.27
CLV34F1 $45,649 $66,140 $1,186,430 $104,571 $5,160 $21,704,581 $18,389,916 1.18
COB12F1 $30,696 $107,775 $1,477,195 $104,964 $2,880 $26,569,160 $15,473,049 1.72
COB12F2 $74,009 $168,939 $1,387,196 $95,450 $3,001 $26,647,552 $36,177,799 0.74
DAL131 $14,441 $18,478 $1,675,982 $87,120 $167 $27,689,548 $7,071,593 3.92
DAL132 $883 $851 $243,863 $9,012 $51 $3,925,776 $1,319,229 2.98
DAL133 $15,005 $55,022 $799,596 $60,941 $175 $14,348,021 $8,227,240 1.74
DAL135 $5,651 $1,013 $120,092 $17,243 $17 $2,220,099 $2,766,107 0.80
DAL136 $4,285 $5,146 $470,895 $32,014 $112 $7,899,823 $3,381,428 2.34
DEP12F1 $72,888 $59,777 $1,720,439 $127,325 $14,091 $30,746,966 $47,579,593 0.65
DEP12F2 $35,860 $37,380 $821,367 $62,362 $7,704 $14,871,142 $16,822,972 0.88
DER651 $7,942 $15,274 $117,554 $22,444 $11,894 $2,699,421 $7,221,062 0.37
DER652 $21,028 $14,973 $248,768 $49,481 $12,187 $5,340,580 $13,255,296 0.40
DRY1208 $6,580 $3,183 $70,200 $7,097 $9,654 $1,490,919 $6,846,238 0.22
DRY1209 $24,351 $1,997 $41,928 $27,439 $36,094 $2,031,925 $11,926,917 0.17
EFM12F1 $42,896 $76,977 $640,964 $66,251 $1,886 $12,779,243 $19,842,971 0.64
EFM12F2 $8,999 $18,432 $49,191 $7,297 $124 $1,295,594 $5,558,612 0.23
F&C12F2 $6,118 $11,899 $286,268 $19,844 $264 $5,000,773 $6,180,256 0.81
FOR12F1 $91,870 $42,688 $330,644 $66,776 $124,228 $10,115,898 $31,191,984 0.32
FOR12F2 $36,690 $29,043 $127,831 $46,774 $15,583 $3,945,199 $8,517,115 0.46
GIF12F1 $13,583 $10,218 $152,578 $32,817 $850 $3,238,011 $5,714,195 0.57
GIF34F1 $4,415 $3,136 $45,308 $6,383 $653 $923,314 $928,572 0.99
GIF34F2 $48,702 $43,623 $935,892 $140,408 $172,678 $20,677,165 $17,912,746 1.15
GLN12F2 $19,589 $47,683 $1,113,655 $67,506 $4,695 $19,317,873 $12,348,191 1.56
GRA12F1 $3,563 $83 $94,340 $6,147 $18 $1,605,579 $4,035,650 0.40
GRA12F2 $33,973 $22,900 $1,345,194 $105,520 $1,413 $23,262,341 $13,388,298 1.74
GRN12F1 $26,012 $21,502 $541,543 $58,129 $14,386 $10,198,628 $12,728,154 0.80
GRN12F2 $51,392 $76,698 $711,732 $129,333 $12,020 $15,125,520 $22,580,410 0.67
GRV1271 $25,344 $21,210 $222,346 $36,103 $164,355 $7,235,496 $8,755,295 0.83
GRV1272 $848 $783 $6,442 $1,304 $695 $155,269 $210,125 0.74
GRV1273 $58,438 $77,723 $385,765 $57,736 $1,304,711 $29,048,975 $25,818,927 1.13
H&W12F1 $9,112 $407 $8,321 $5,854 $249 $369,104 $6,060,581 0.06
H&W12F3 $36,504 $27,801 $276,584 $69,412 $13,819 $6,538,130 $12,583,923 0.52
HUE141 $2,458 $5,544 $207,875 $11,248 $102 $3,502,869 $2,371,955 1.48
HUE142 $15,967 $4,526 $1,026,344 $31,938 $4 $16,630,158 $14,793,905 1.12
IDR251 $10,452 $6,998 $19,729 $2,845 $129 $618,967 $8,168,768 0.08
IDR253 $49,460 $133,242 $3,138,039 $162,204 $699 $53,702,899 $26,875,637 2.00
INT12F1 $1,031 $1,760 $94,133 $6,200 $116 $1,591,511 $1,550,953 1.03
INT12F2 $35,255 $44,544 $298,110 $26,319 $41,208 $6,866,709 $29,521,037 0.23
JUL662 $4,868 $2,697 $17,745 $4,688 $4,004 $524,160 $1,764,077 0.30
KAM1291 $20,826 $15,129 $189,302 $28,928 $57,794 $4,809,383 $10,460,518 0.46
KAM1292 $14,361 $7,199 $25,587 $22,142 $61,036 $2,009,061 $3,551,360 0.57
KAM1293 $17,659 $12,976 $162,926 $31,316 $117,194 $5,273,276 $7,879,804 0.67
KET12F1 $4,239 $3,455 $8,401 $14,375 $1,612 $494,563 $4,190,394 0.12
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October 30, 2024
Feeder O&M O&M Veg. Outage Repair Wildfire Total Benefit Cost ($) Benefit-
Name Reduction Management Reduction Reduction Reduction ($)over the of Under- Cost Ratio
Benefit Reduction Benefit Benefit Benefit time horizon grounding (BCR)
($/yr.) Benefit($/yr.) ($/yr.) ($/yr.) ($/yr.) of 76.5 years Project
KET12F2 $23,690 $14,290 $298,635 $46,252 $34,474 $6,433,610 $9,626,263 0.67
K001298 $28,529 $22,327 $137,066 $25,374 $139,779 $5,442,908 $11,459,623 0.47
K001299 $31,223 $17,175 $124,193 $27,724 $58,929 $3,996,433 $14,297,268 0.28
L1312F1 $9,044 $10,861 $2,931 $2,825 $16,367 $647,894 $7,154,287 0.09
L1B12F2 $8,617 $6,567 $87,805 $18,434 $6 $1,871,908 $7,740,000 0.24
L1B12F3 $22,626 $69,234 $835,314 $55,540 $297 $15,153,833 $8,665,521 1.75
LOL1266 $26,358 $8,587 $266,365 $12,287 $51,830 $5,633,316 $14,252,548 0.40
LOL1359 $6,403 $4,216 $130,539 $5,790 $1,623 $2,290,328 $4,491,816 0.51
L0012F1 $26,375 $23,144 $373,821 $48,126 $20,787 $7,588,436 $15,360,515 0.49
L0012F2 $30,232 $68,162 $337,688 $64,533 $25,054 $8,103,575 $14,066,031 0.58
LTF34F1 $50,287 $24,888 $233,207 $70,584 $19,469 $6,142,156 $14,591,603 0.42
M15514 $2,917 $3,128 $385,141 $13,741 $2,295 $6,277,613 $1,025,668 6.12
M15515 $1,037 $244 $30,261 $1,365 $110 $508,966 $527,854 0.96
M23621 $1,697 $806 $20,639 $2,712 $96 $400,040 $1,670,575 0.24
MEA12F1 $3,373 $8,999 $113,561 $10,889 $22 $2,109,543 $1,765,510 1.19
MEA12F2 $20,842 $58,552 $773,318 $71,851 $215 $14,256,106 $13,023,921 1.09
MEA12F3 $2,976 $2,220 $7,451 $2,861 $9 $239,200 $1,508,814 0.16
MIL12F3 $4,307 $6,560 $162,648 $11,717 $8 $2,855,595 $958,065 2.98
MIS431 $4,851 $5,821 $145,064 $17,743 $37 $2,674,887 $2,742,918 0.98
MLN12F1 $68,445 $39,756 $911,732 $138,831 $8,703 $17,997,362 $27,703,175 0.65
MLN12F2 $61,695 $98,812 $920,665 $133,104 $3,777 $18,777,154 $31,648,995 0.59
NE12F3 $13,314 $9,289 $425,539 $38,608 $127 $7,505,550 $4,368,913 1.72
NE12F4 $4,453 $2,355 $103,307 $8,158 $68 $1,824,309 $1,390,713 1.31
NRC351 $831 $769 $296 $1,421 NaN $51,146 $322,341 0.161
NW12F1 $11,385 $42,836 $511,133 $35,644 $7,437 $9,379,461 $6,520,124 1.44
NW12F2 $6,219 $18,216 $471,884 $52,442 $3,543 $8,514,157 $2,176,352 3.91
NW12F3 $3,896 $13,749 $234,271 $18,044 $778 $4,173,637 $4,693,211 0.89
ODN731 $33,304 $80,048 $1,827,482 $125,866 $6,414 $31,958,544 $18,515,509 1.73
ODN732 $6,966 $13,150 $74,625 $40,357 $2,086 $2,114,768 $2,915,590 0.73
OLD721 $48,316 $40,403 $972,273 $118,885 $4,052 $18,251,115 $22,581,848 0.81
0R112F1 $60,562 $37,003 $716,595 $151,133 $5,826 $14,970,497 $21,064,418 0.71
OR112F2 $7,388 $11,172 $19,401 $16,703 $1,078 $859,291 $3,326,213 0.26
OR112F3 $35,106 $64,021 $779,323 $92,301 $6,445 $15,064,195 $13,634,614 1.10
OR01280 $13,040 $12,339 $268,031 $50,216 $16,285 $5,548,281 $7,569,623 0.73
OR01281 $29,073 $55,752 $392,900 $51,969 $109,986 $9,861,140 $18,457,982 0.53
OR01282 $12,513 $24,898 $132,355 $24,079 $73,177 $4,116,334 $8,062,702 0.51
OSB521 $6,803 $10,331 $196,508 $23,270 $192 $3,655,136 $5,319,648 0.69
OSB522 $8,184 $122,034 $1,259 $12,008 $2,365 $2,248,397 $11,620,708 0.19
PDL1202 $974 $496 $33,873 $2,423 $300 $586,818 $294,681 1.99
PDL1203 $2,723 $2,039 $50,857 $5,101 $1,831 $964,275 $731,657 1.32
PDL1204 $9,817 $3,659 $48,239 $8,360 $3,621 $1,136,092 $7,777,763 0.15
PF213 $3,248 $1,991 $179,904 $8,586 $85 $2,987,792 $2,770,413 1.08
PIN441 $8,871 $26,902 $545,064 $62,492 $155 $9,919,773 $4,657,020 2.13
PIN442 $5,506 $16,238 $99,372 $20,906 $86 $2,190,698 $5,233,884 0.42
PIN443 $25,128 $75,672 $1,282,931 $105,416 $618 $22,965,806 $12,475,591 1.84
PRA221 $1,209 $1,851 $20,382 $1,610 $79 $387,417 $0 NaNa
PRA222 $1,425 $2,450 $149,320 $5,814 $44 $2,451,941 $1,567,063 1.56
PRV751 $13,834 $15,519 $251,781 $47,241 $0 $5,062,133 $4,947,875 1.02
PRV752 $57,310 $68,305 $1,697,811 $149,909 $0 $30,420,384 $16,196,161 1.88
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October 30, 2024
Feeder O&M O&M Veg. Outage Repair Wildfire Total Benefit Cost ($) Benefit-
Name Reduction Management Reduction Reduction Reduction ($)over the of Under- Cost Ratio
Benefit Reduction Benefit Benefit Benefit time horizon grounding (BCR)
($/yr.) Benefit($/yr.) ($/yr.) ($/yr.) ($/yr.) of 76.5 years Project
PVW241 $15,895 $3,381 $450,258 $24,025 $282 $7,612,928 $16,057,115 0.47
PVW243 $1,700 $2,042 $1,043 $152 $11 $76,291 $0 NaNa
RAT233 $79,252 $111,069 $5,988,275 $222,348 $2,073 $98,707,160 $31,387,900 3.14
RDN12F1 $8,719 $1,280 $24,333 $5,487 $17,845 $888,933 $1,342,455 0.66
RDN12F2 $6,596 $1,002 $9,883 $3,892 $8,637 $462,625 $1,241,310 0.37
SAG741 $49,682 $131,856 $3,681,796 $325,351 $3,933 $64,632,250 $20,258,720 3.19
SAG742 $31,891 $51,561 $2,338,081 $180,658 $872 $40,128,124 $21,069,397 1.90
SE12F2 $16,125 $27,985 $908,244 $49,817 $24,192 $15,822,134 $6,884,458 2.30
SE12F4 $3,580 $8,836 $405,968 $33,183 $81,842 $8,222,878 $3,648,567 2.25
SE12F6 $982 $336 $5,532 $686 $62 $117,113 $407,237 0.29
SIP12F4 $1,623 $746 $54,605 $3,389 $10 $930,696 $574,939 1.62
SLK12F1 $37,123 $168,062 $340,575 $34,760 $49,954 $9,719,218 $14,822,750 0.66
SLK12F2 $15,008 $4,856 $226,883 $35,754 $7,200 $4,465,936 $9,548,410 0.47
SLK12F3 $22,723 $6,701 $14,638 $11,016 $34,261 $1,377,217 $17,700,697 0.08
SLW1348 $5,844 $5,581 $80,203 $11,541 NaN $1,590,434 $5,639,092 0.281
SLW1358 $1,790 $2,049 $45,694 $3,021 $1,733 $836,865 $631,323 1.33
SLW1368 $4,397 $2,134 $99,798 $10,002 $16,094 $2,041,427 $3,600,332 0.57
SOT521 $4,638 $2,087 $78,136 $8,878 $796 $1,457,351 $2,096,482 0.70
SOT523 $15,851 $3,586 $80,658 $15,973 $10,840 $1,956,381 $11,867,926 0.16
SPI12F1 $5,260 $4,573 $38,266 $6,202 $23 $837,448 $2,273,394 0.37
SPL361 $20,748 $66,124 $2,031,145 $130,430 $3,137 $34,709,790 $5,948,465 5.84
SPT4S21 $44,906 $77,746 $3,601,926 $233,095 $5,814 $61,100,026 $23,820,987 2.56
SPT4S23 $2,118 $1,820 $190,786 $10,459 $54 $3,163,877 $1,650,836 1.92
STM631 $45,800 $185,718 $3,889,751 $223,800 $5,269 $67,063,606 $11,195,018 5.99
STM633 $12,919 $22,229 $553,919 $49,751 $1,021 $9,863,571 $5,898,158 1.67
STM634 $8,195 $9,842 $68,609 $9,192 $350 $1,482,817 $3,031,607 0.49
SUN12F1 $1,074 $4,275 $405,966 $20,879 $315 $6,667,457 $1,619,437 4.12
SUN12F2 $34,189 $91,263 $1,430,140 $104,749 $20,844 $25,916,678 $21,697,324 1.19
SUN12F4 $17,461 $15,924 $474,761 $33,791 $2,958 $8,399,955 $9,322,910 0.90
SUN12F5 $48,999 $30,778 $501,715 $99,930 $94,708 $11,964,605 $22,257,740 0.54
SWT2403 $15,303 $12,614 $93,689 $10,408 $48,033 $2,775,557 $7,847,782 0.35
TEN1254 $2,663 $1,941 $44,034 $2,980 $213 $799,013 $3,752,313 0.21
TEN1255 $2,114 $1,967 $99,302 $4,125 $661 $1,667,504 $3,156,702 0.53
TEN1256 $7,801 $10,873 $74,810 $6,441 $0 $1,540,416 $7,488,853 0.21
TEN1257 $2,510 $1,531 $43,085 $1,818 NaN $754,519 $1,964,556 0.38b
VAL12F1 $83,189 $55,397 $1,516,823 $183,083 $56,056 $29,205,848 $29,185,922 1.00
VAL12F2 $26,612 $23,571 $192,542 $72,460 $7,355 $4,972,201 $8,816,281 0.56
VAL12F3 $24,713 $35,034 $436,720 $85,608 $5,703 $9,061,036 $7,718,155 1.17
WAK12F1 $9,753 $37,640 $2,690,845 $181,035 $2,517 $45,041,523 $7,846,832 5.74
WAK12F2 $7,075 $31,133 $175,309 $19,477 $481 $3,599,208 $3,530,871 1.02
WAK12F3 $2,124 $5,107 $113,609 $9,709 $107 $2,014,165 $2,877,197 0.70
WAK12F4 $22,646 $89,009 $668,200 $56,624 $9,703 $13,044,507 $14,800,359 0.88
WAL542 $2,475 $7,493 $21,310 $3,630 $444 $544,973 $2,794,603 0.20
WAL543 $3,681 $13,543 $46,630 $9,881 $531 $1,144,852 $3,184,585 0.36
WAL544 $12,137 $24,361 $135,850 $25,917 $541 $3,064,742 $12,116,118 0.25
WAL545 $4,703 $15,002 $97,268 $12,912 $205 $2,005,430 $2,442,398 0.82
WAS781 $5,895 $1,181 $6,035 $3,469 $17,600 $526,916 $906,922 0.58
WE11289 $22,017 $18,487 $213,332 $32,762 $104,536 $6,029,610 $19,744,578 0.31
WIL12F2 $1,223 $166 $3,213 $604 $1,494 $103,286 $0 NaN,
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October 30, 2024
a The Avista provided cost is$0, so the BCR cannot be calculated.
b The BCR calculation excludes one or more benefits due to unavailable input data.
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Recommendations for Future Study
Exponent has several recommendations for areas of further study and consideration. These are
not intended to distract from the validity of the current Benefit Cost Ratio values. In fact, it is
expected that consideration of these items will result in a net increase in Benefit Cost Ratios on
most feeders.
1. The present analysis created generic fragility curves for wood poles based on
assumed new pole failure rates, location, age, and asset condition score. There
was insufficient data to consider including the conductor span, diameter, material
and quantity, which would result in more precise estimates of the fragility curves,
when combined with information such as the class of pole.'It is recommended
that Avista link conductor and pole data to enable this analysis and refinement of
fragility curves.
2. Asset condition codes and remaining strength were only available for some poles.
Future analyses will be more precise if condition and remaining strength data is
collected for the remaining wood poles.
3. Benefit analyses have all been conducted on the basis of the present system
configuration and condition. In reality, assets will continue to age, new feeders
will be added and change configuration, additional connections to the system will
be incorporated, customer usage may change, maintenance will alter the
propensity for outages, and changing weather patterns may affect wildfire
consequences and outage rates. Future assessments could consider these issues,
which would result in different realized benefits of undergrounding projects in
different years.
4. Avista's current wildfire risk analysis determines relative consequences based on
fires started at specific locations along their feeders. Future analysis could
consider consequences in terms of lives lost, injuries, acres burned, and structures
burned directly, and it could also consider the probability of ignition
quantitatively.
5. Wildfires not only cause direct loss of life and destroy buildings, farmland, and
forests, but also release significant amounts of smoke, which can have a
substantial impact on human health. These impacts on human health from air
quality degradation have not been considered as part of this study,but could be
considered in future studies.
6. This cost benefit analysis has considered projects individually, as opposed to
considering the system as a whole. For example, the sequencing of
undergrounding projects has not been considered. Future studies could consider
E.g.,Darestani,Y.M.and Shafieezadeh,A.,2019.Multi-dimensional wind fragility functions for wood utility
poles.Engineering Structures,183,pp.937-948.
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October 30, 2024
the phasing of projects, such that not all projects begin in a nominal year zero, to
determine the overall benefit cost ratio of an undergrounding program consisting
of multiple feeders.
7. The current cost benefit analysis has considered only feeders identified and costed
by Avista. Future studies could dynamically identify sections of feeders that yield
the most significant benefit from undergrounding, and then determine final
benefit cost ratios to inform decisions on which feeders to underground.
8. Aesthetic benefits from undergrounding distribution lines, such as the change in
property values, were not considered, as there is not currently reliable information
on how undergrounding distribution lines impact property values.' Studies do
indicate that views of overhead transmission lines negatively affect property
values.9
9. Construction-associated injuries and fatalities stemming from undergrounding
projects were not considered because Avista does not currently consider them for
other projects. This could be considered in the future,but it is recommended that
this be treated consistently across Avista projects, and not just for
undergrounding.
10. Avista could consider how undertaking undergrounding projects changes the
demand for labor.
11. Avista could consider the economic impact of the undergrounding projects on rate
payers.
8 Industrial Economics,Inc.The benefits,costs,and economic impacts of undergrounding New York's electric grid.
June 27,2023.p.37.
9 Des Rosiers,F.,2002.Power lines,visual encumbrance,and house values.J.Real Estate Res.23(3).
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October 30, 2024
Rationale for Incorporating Scenario Risk Analysis
The cost-benefit analysis relies on quantitative and probabilistic methods to determine annual
losses attributed to wildfires. The prediction of low-probability, high-consequence natural hazard
events, such as wildfires, and their impacts on populations and property is associated with large
uncertainty, dependencies between the underlying variables, and likely non-stationarity due to
the effects of climate change. As a result, analysis of the risks of low-probability, high-
consequence events poses significant challenges and motivates the use of complementary
methods beyond conventional probabilistic risk assessment, such as scenario risk analysis.
Examples from several fields of study demonstrate that scenario risk analysis has the capacity to
improve understanding of the exposure to rare events, identification of their physical and social
impacts, and assessment of the benefits associated with potential mitigation and preparation
strategies.
Fat-tailed distributions and uncertainty
Probabilistic hazard assessments generally utilize frequency-size distributions to estimate the
occurrence of extreme events. Determining the probability distributions of extreme events is
difficult because of their rare occurrence,but research over several decades has shown that the
distributions associated with many natural hazard characteristics and their impacts follow power-
law type distributions (L e.,P(x)— x'). The probability functions of power-law type
distributions, such as the Pareto distribution, exhibit a slow (polynomial)rate of decay of
increasingly large observations. This means that tail events are much more likely compared to a
Gaussian distribution in which the probability decays exponentially. Power-law distributions are,
therefore, known to be `fat-tailed' (i.e., having a higher probability of tail or extreme events), as
opposed to thin-tailed Gaussian distributions.
There is large uncertainty in predicting low-probability, high-consequence events because
observations of such events are very sparse, and the observational time span is typically not long
enough. Therefore, the distributions fitted to the observed data tend to match the central
tendencies of the data well but may underestimate the rare tail events,10 whereas distributions
fitted to the extreme tail events must cope with very small, if any, associated observations. The
10 King,G.,&Zeng,L.(2001).Logistic regression in rare events data.Political analysis,9(2),137-163.
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October 30, 2024
large uncertainty in the occurrence of the tail events may lead to hazard and risk estimates that
are highly sensitive to the distribution parameters and modeling assumptions.11,12,13,14
Examples of fat-tailed frequency-size distributions of natural hazard variables include the
discharge from flood events,15 the volume of landslides," and the areas burned by wildfires.17 In
addition, even if the characteristics of the hazard are not fat-tailed, many studies have shown that
the damages imposed by the hazards tend to be fat-tailed due to the properties of the underlying
impacted population centers;18 for example, the economic damages from tropical cyclones in the
U.S. between 1900 and 2012,19 and the damage imposed by tornadoes in the U.S.11 were recently
shown to be fat-tailed.
Because of the fat-tail property of the impacts of hazard events, empirical evidence demonstrated
that the few most damaging events contribute highly to the cumulative damage impacts of
several hazards. For example, a study of flood damage in Germany attributed 20% of total
cumulative damages to events rarer than a probability of 1%per year.2'Another example is an
analysis of the cost of 174 weather disasters published by the U.S.National Oceanic and
Atmospheric Administration, in which the few most costly disasters dominate: the single most
costly disaster accounts for approximately 15% of the cumulative impacts, and the top five
events account for approximately 31%. 21 Similarly, in a dataset of earthquake-related fatalities
from 100 events, the same study finds that the single most damaging earthquake contributes 14%
relative to the 100 events, and the ten most damaging events contribute 65%.21 Similar trends
Jo,H.H.,&Ko,Y.L.(2014).Large variance and fat tail of damage by natural disaster.In Vulnerability,
Uncertainty,and Risk:Quantification,Mitigation,and Management(pp.2744-2753).
12 Weitzman,M.L.(2011).Fat-tailed uncertainty in the economics of catastrophic climate change.Review of
Environmental Economics and Policy.
13 Conte,M.N.,&Kelly,D.L.(2021).Understanding the improbable:A survey of fat tails in environmental
economics.Annual review of resource economics,13,289-310.
14 Malamud,B.D.(2004).Tails of natural hazards.Physics World,17(8),25.
15 Malamud,B.D.,&Turcotte,D.L.(2006).The applicability of power-law frequency statistics to floods.Journal of
hydrology,322(1-4),168-180.
16 Brunetti,M.T.,Guzzetti,F.,&Rossi,M.J.N.P.I.G.(2009).Probability distributions of landslide volumes.
Nonlinear Processes in Geophysics,16(2),179-188.
17 Malamud,B.D.,Millington,J.D.,&Perry,G.L.(2005).Characterizing wildfire regimes in the United States.
Proceedings of the National Academy of Sciences,102(13),4694-4699.
18 Gabaix,X.(1999).Zipf's Law and the Growth of Cities.American Economic Review,89(2),129-132.
19 Conte,M.N.,&Kelly,D.L.(2018).An imperfect storm:Fat-tailed tropical cyclone damages,insurance,and
climate policy.Journal of environmental economics and management,92,677-706.
20 Merz,B.,Elmer,F.,&Thieken,A.H.(2009).Significance of"high probability/low damage"versus"low
probability/high damage"flood events.Natural Hazards and Earth System Sciences,9(3),1033-1046.
21 Etkin,D.A.,Mamuji,A.A.,&Clarke,L.(2018).Disaster risk analysis part 1:the importance of including rare
events.Journal of homeland security and emergency management,15(2),20170007.
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October 30, 2024
were found for fatalities corresponding to industrial disasters, U.S. tornadoes, and structural
fires.
Scenario risk analysis as a complementary method
Standard probabilistic risk assessment may underestimate the impacts of rare events because of
the difficulty to estimate their probabilities and quantify their impacts, and the sensitivity of the
risk to the variables of the hazard and modeling decisions. In addition, some studies suggest that
risk analysis based on fat-tailed power laws may still underestimate rare risk events.22
Specifically, the presence of outliers (defined as extreme events which may be significantly
larger than the predictions of power-law distributions) has been documented.
In response to these challenges, research studies have advocated for explicitly including rare
events or worst-case scenarios in disaster risk analysis, or focusing on tail (or rare) exposures
instead of the mean exposure.23 An example of this approach is the improvements to the National
Seismic Hazard Maps of Japan in response to the devastating impacts of the 2011 Tohoku
earthquake; these improvements included the incorporation of low-probability earthquakes
which were not previously incorporated in the analysis, and for which scientific evidence exists,
even if they have not been historically observed. Other studies have emphasized the importance
of possibilistic thinking:24 complementing probabilistic thinking by envisioning worst-case
scenarios and including them within risk analyses and planning processes, with the goal of
identifying weaknesses in complex systems and strengthening networks.21 Conducting scenario
(or deterministic)risk analysis, in addition to standard probabilistic assessments, is an effective
method to include the effects of rare events in risk analysis. As such, scenario risk analysis
would complement the cost-benefit analysis (which includes probabilistic components) to further
understand rare events and inform decision making when prioritizing undergrounding projects as
risk mitigation measures.
An example of applying this type of thinking comes from the nuclear industry, which refers to
"beyond design basis" events. Plants are typically designed for, e.g., very rate flood elevations,
but evaluate what happens when flood waters exceed that elevation, often resulting in further
mitigations such as installing emergency pumps and moving critical equipment to higher
elevations.
Application to Avista's Proposed Undergrounding Projects
While some of the proposed undergrounding projects have BCR values less than 1, components
of the analysis that consider contributions to the "benefits" consider both the consequence and
22 Sornette,D.(2009).Dragon-kings,black swans and the prediction of crises.arXiv preprint arXiv:0907.4290.
23 Taleb,N.N.(2008).The fourth quadrant:a map of the limits of statistics.An Edge original essay,Edge.
24 Clarke,L.(2006).Worst cases:Terror and catastrophe in the popular imagination.University of Chicago Press.
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October 30, 2024
the frequency of the consequence. In particular, the wildfire frequency, which is typically low, is
considered in FEMA's calculation of wildfire losses, which informed this study. However, a
catastrophic wildfire could have drastic consequences far exceeding the cost of any
undergrounding projects, if it were to occur, potentially causing irreparable harm to Avista and
its customers. It is thus worth considering the severity of the consequences, independent of the
frequency of their occurrence, as part of the decision-making process for undergrounding.
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'Aiiv _
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Preventing and Mitigating Vegetation Fires
While Performing AVISTA Work
Publication Date: November 10,2025
2

Employee Authorization to Stop Work
To:All Avista Employees
From: Heather Rosentrater
The safety of our employees is a top priority,and Avista continually communicates the importance of creating safe
work habits. It is vital for every employee to take personal responsibility for creating a safer work environment and
demonstrating a commitment to safety every second of every day-our families,friends,coworkers and the public
expect nothing less. Please take the time to work safely. Be mindful of our safety principles—rushing,frustration,
fatigue,and complacency can cause or contribute to actions that increase the risk of injury,such as eyes not on
task, mind not on task, being in the line of fire,and losing balance/traction/grip.Our commitment,which is shared
among our leadership team, is to make safety a priority in all operations.This means that emphasis will be placed
on activities that support employees' use of safety principles and rules,which are established for their protection.
Will you help contribute to a safer work environment?We need your commitment.As you set out to work each
day,start out with a conscious intention of doing your work in a safe manner.As a critical element of our priority
on safety,we have adopted the following"Authorization to Stop Work"which we clearly post at each of our work
locations.All employees have the right to report to their supervisor, manager,Safety Department or Human
Resources Department, unsafe working situations without fear of reprisal. Please help foster a safety culture that
achieves results through employee involvement.Your efforts are supported by the leadership at Avista who model
and encourage these safe behaviors and are accountable for their achievement.
********************Authorization to Stop Work********************
As an employee at Avista, I have been given the authority,without fear of reprimand or retaliation,to
immediately stop and remove myself from any work activity that presents a danger to me, my co-workers,or the
public. It is my responsibility to get involved,question,and rectify any situation that is identified as being out of
compliance with safety policies and safe practices,and to report any unsafe conditions or acts to supervision. I
have the responsibility to question and challenge any work activity that involves a violation of an established safety
policy.
3

TOPICS
TOPICS...........................................................................................................................................................................4
SUMMARY.....................................................................................................................................................................4
TARGET AUDIENCE .........................................................................................................Error! Bookmark not defined.
1 Safety..........................................................................................................................................................................4
2 General Requirements................................................................................................................................................5
DEFINITIONS..................................................................................................................................................................8
SUMMARY
This document establishes requirements for AVISTA personnel and contractors to follow when traveling to worksites,
performing work,or operating outdoors in any forest, brush,or grass-covered land.The information in this
document supplements the instructions contained in local,state,and federal fire regulations and permits. If a local or
state fire regulation or permit contains more stringent requirements than those in this document,the more stringent
requirements must be followed.
APPLICABILITY
This document applies to all AVISTA employees and contractors working on or near AVISTA facilities located in any
forest, brush,or grass-covered lands, and using equipment,tools,and/or vehicles which use could result in the
ignition of a fire.
Wildfire Awareness training is required for AVISTA employees who are involved in the prevention and mitigation of
fires,and such training should be completed annually between January 1 and June 1.
Document Management:
Version History:
Revision# Name Date Change
N/A Matt Ugaldea 11/10/2025 Signed&Published by Avista
1 Safety
1.1 Performing utility work in any forest, brush,or grass-covered lands presents a danger of fire, in addition to the
hazards inherent to utility work.
1.2 Adhering to the directives outlined in this document is essential to mitigating fire danger and protecting
personnel,the public, utility infrastructure,and the environment.
4

1.3 AVISTA employees and contractors shall perform all operations or actions within hazardous fire areas in
accordance with AVISTA's"Incident Prevention Manual (IPM)," (Standalone Programs)
2 General Requirements
2.1 The Manager/Foreman must ensure the following actions are taken:
1. Identify and comply with the local,state,and federal fire authority permits and/or restrictions in the area
where the work is to be performed, including Federal Energy Regulatory Commission (FERC) project
requirements.
2. Ensure a tailboard is conducted for all work activities and review AVISTA's Fire Weather Dashboard during
the safety tailboard to facilitate discussions about the work being performed and the planned mitigations.
Discussions should include the following topics:
a. The activities being performed;
b. The mitigations being taken to reduce the risk of spark events;
c. Fire prevention and extinguishing equipment on vehicles;
d. Evacuation routes;and
e. Awareness of the communications protocols needed on the jobsite.
2.2 Any person in charge (PIC) of working personnel must review AVISTA's Fire Weather
Dashboard locally, changing meteorological conditions, and remain alert to the potential for
increased fire danger while work is in progress.
2.3 When traveling to the jobsite, or when operating off designated roadways or overland, all
personnel must take the following actions:
1. Do not drive overland (through fields,forests,etc.)except when performing the required work or during
an emergency.
2. When required to drive off designated roadways, maintain situational awareness and watch for potential
ignition sources,especially when operating vehicles on dry brush,grass,or other vegetation.
3. Ensure that required tools are available on vehicles.
a. Standard (SUVs, light pickup,etc.)vehicle:
i. One shovel
ii. One fire extinguisher in good working order, minimum U.L. rated 1A1013C(Check with
Fleet on what we provide)
b. Trucks,four-wheel drive vehicles,and all-terrain vehicles(ATVs):
i. One shovel
ii. Silver pressurized 2.5 gallon cans
c. Heavy machinery or equipment(e.g.tractors,tub grinders,whole tree chippers,excavators,
bulldozers):
i. One shovel
ii. One fire extinguisher in good working order, minimum U.L. rated 1A1013C
NOTE-When multiple vehicles are traveling together to a job site,each vehicle is not required to carry a
full set of tools.This also applies to heavy machinery when tools cannot be properly secured. However,
the required tools must be available for personnel at the jobsite.
4. When possible, ensure vehicles are parked in an area cleared of vegetation.
a. If unable to park in a cleared area,
i. Look under the vehicle once parked to ensure that dry vegetation is not in contact with
any of the exhaust systems,which is a possible ignition source
5

ii. Ensure the proper fire extinguishing tools are on the vehicle,as described above.
Maintain situational awareness and monitor for potential ignitions.
5. .
6. Turn off the motors of unoccupied vehicles when parking off road unless the vehicle and the motor must
remain running for work purposes. Maintain situational awareness for potential ignitions.
2.4 Before starting work on or near any forest, brush, or grass-covered lands, all personnel must
perform the following actions:
1. Review AVISTA's Fire Weather Dashboard
2. Review and understand the daily Industrial Fire Protection Levels(IFPL)or Fire Restrictions in the
geographic area of operations.
a. https://www.dnr.wa.gov/burn-restrictions
b. https://www.idl.idaho.gov/fire-management/fire-restrictions-finder/
c. https://www.mtfireinfo.org/pages/restrictions
3. Participate in a tailboard for all work activities to facilitate discussions about the work being performed
and planned mitigations.
2.5 The specific fire-fighting tools required at jobsites must comply with state law. An option
must be provided for personnel or first responders to have additional onsite tools. Under no
circumstances will any AVISTA employee or contractor be asked to fight any fire beyond their
experience and training.
2.6 When working at the job site, all personnel must perform the following actions:
1. Observe all laws, rules,and regulations of local,state,and federal fire authorities having jurisdiction over
areas in which they are working.
2. Perform mitigation measures as described in this standard during any operation or action that could
result in an uncontrolled fire, including wetting the general area.
3. Do not start any fire that could escape control through careless or negligent actions.
4. While performing stationary ground level jobs or activities from which a spark,fire,or flame may originate
(e.g.,welding,cutting,grinding), all flammable material (e.g.,grass, leaf litter, including snags)must be
removed down to the mineral soil around the operation in a 10-foot radius.
a. IF the jobsite is not stationary, OR IF it cannot be sufficiently cleared because of environmental
concerns(e.g.,vegetation clearances along electric distribution circuits,erosion),AND the IFPL is
1,THEN there must be a Working Fire Watch assigned at the jobsite.
b. IF the jobsite is not stationary, OR IF it cannot be sufficiently cleared because of environmental
concerns(e.g.,vegetation clearances along electric distribution circuits, erosion),AND the local
condition are"high"or"extreme,"THEN there must be a Dedicated Fire Watch equipped with at
least 120 gallons of water with a 200 feet of hose capable of at least 40 pounds per square inch
(psi)at the nozzle.
When responding to an emergency,follow all the applicable requirements including this standard, if
possible.
2.7 If a fire ignites on the jobsite, personnel must perform the following actions:
1. Call emergency services(9-1-1)to report the ignition, even if the fire has been suppressed.
2. Take safe, reasonable suppression actions consistent with the person's experience and training.
3. If necessary,evacuate to a safe location.
6

4. Upon request, provide relevant information to emergency responders to either assist in their fire
suppression efforts or for the protection of people and/or property. Do not speculate as to the cause of
an ignition, unless such information is necessary for the safety of any person.'
5. After contacting emergency services,the field personnel must call the Distribution Operator(DO)to
report a spark event.
6. Notify the Claims Department to report the event and provide any requested information.
7. Report the incident to their direct supervisors and follow any further reporting procedures required.
END of Requirements
'Speculating the cause of an ignition prior to an investigation can lead to the dissemination of misinformation and
cause confusion.
7

DEFINITIONS
Dedicated Fire Watch:A crew member assigned solely to monitor for potential or new fire ignitions at the jobsite
while work is being performed.This person must maintain complete situational awareness,assist promptly
extinguishing fires,and stop work when necessary to ensure safety.
Designated roadways: Paved,graveled,and/or maintained dirt roads used by AVISTA personnel.
Disking:A disc-shaped tool used to till soil for vegetation removal.
Fire Tools:The tools used to fight fires. Fire tools include the following equipment:
• Shovel:A standard, round point shovel at least 42 inches long.
• McLeod:A hand tool used for raking and scraping.
• Pulaski: an axe-like fire hand tool used for cutting,chopping or grubbing.
• Backpack pump:A portable S-gallon water pack with a hose and nozzle used to extinguish fires.These can
be collapsible backpacks, plastic or steel tanks.
Fire Weather Watch:A type of watch issued by the National Weather Service to alert fire officials and firefighters
of potentially dangerous fire weather conditions in the next 24 to 36 hours.
Major Work Operation:A job where work activities or staging of resources are concentrated in and around a
designated area.These jobsites where people stage and conduct construction-type activities are typically large in
scale.
Masticating: Reducing vegetation into small chunks to assist in removing small trees(e.g.snags).
Overland Travel:Areas that are overgrown with grass and/or brush without a visible road.
Red Flag Warning:A warning issued by the National Weather Service to alert fire officials and firefighters of
potentially dangerous and imminent fire weather conditions.
Stationary Work:Work being performed in a single location for an extended period that is neither intended nor
expected to move.
Working Fire Watch:A crew member responsible for fire detection, risk mitigation,and total situational awareness
while work is being performed in addition to normal assigned work duties.This crew member is also responsible
for helping to extinguish fires and stop work,when required,due to safety hazards.
IMPLEMENTATION RESPONSIBILITIES
The Wildfire Resiliency Program Manager,who oversees the Wildfire Resiliency Program, is responsible for
approving and updating this standard,and ensuring its proper distribution. Directors overseeing field and
operational teams within the following organizations must ensure that their employees,whose actions could pose
a fire risk,are informed of and comply with this standard:
• Electric Operations
• Gas Operations
• GPSS
• Enterprise Technology
• Customer Operations
• Shared Services
8

REFERENCE DOCUMENTS
Developmental References
General:
• Code of Safe Practices
Utility Standards:
Supplemental References:
• National Wildfire Coordinating Group, NWCG User Guide for Glossary of Wildland Fire
• United States Department of Agriculture(USDA) Forest Service, "National Fire Danger Rating System"
APPENDICES
NA
ATTACHMENTS
NA
9

AllWR I d f i r ea
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Miatiagation
Plan
2026
Appendix
Distribution
Tree Program
H

AIX idod _ A Distribution Risk Tree Program
MAY 2024
PROGRAM
ASSESSMENT
iapetus
infrastructure services
PREPARED BY:
Adam Warf
Dr. Philip Charlton
Steve Hallmark
Iapetus Infrastructure Services, LLC
3900 Essex Lane, Suite 775
Houston, TX 77027
LEGAL DISCLAIMER:Recommendations made in this report are for Avista's internal use only.IIS is not responsible for Avista's action(s)or
inaction in response to these recommendations.Assumptions made by IIS in the composition of this report were made based upon information
collected by and from Avista. Gaps in information are noted,but numbers may be skewed as a result of missing or inaccurate data provided.

iapetus
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Distribution Risk Tree Program Assessment for Avista Utilities
Executive Summary
Introduction
In 2020, Avista Utilities (Avista) began a risk tree inspection program on the distribution
system. Trees meeting predetermined risk criteria are scheduled for tree maintenance
within six months of identification. Its first full annual system assessment was completed
in 2022.
In June 2023, Avista agreed to the following terms with the Idaho Public Utilities
Commission (PUC):
For the Distribution Risk Tree program, the Company will have a
third party conduct a study, within a year of Commission Order,
to see what the most efficient vegetation management cycle
should be in their service area (i.e., 2- or 3-year cycles).
In response to the Commission Order (the "Order") above, Avista contracted Iapetus
Infrastructure Services ("IIS") to evaluate its current Distribution Risk Tree Program and
provide recommendations for enhancing its approach to timing of inspections and
subsequent mitigation measures.
Assessment Process
As directed by Avista, IIS performed a detailed review of Avista's Distribution Risk Tree
Program to assess the optimum frequency of maintenance per service area (i.e., one-,
two- or three-year cycles). All areas of review were made within the context of Avista's
Wildfire Resiliency Plan.
The team utilized the following process for this assessment:
1. Review Avista's Enhanced Vegetation Management and Wildfire Resiliency
Plans.
2. Assess Avista's tree-specific performance including tree-related outage data and
work completion records.
3. Interview Avista's Vegetation Management team.
4. Develop and document recommendations.
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Key Observations
Avista has developed a Risk Tree Program leveraging their internal experience and
history of tree outages and program performance, as well as collaboration with leading
wildfire mitigation programs at electric utilities with more mature and robust programs.
Based upon this review, the IIS team finds that Avista's approach to managing the risk
associated with utility-caused wildfires as an annual cycle is a reasonable and
responsible approach. IIS has identified the following major areas of focus to enhance
the foundation of Avista's Risk Tree Program and become a more progressive, best-in-
class program.
Observation Comments
Risk Tree Considering the impact that drought and tree mortality has had on
Cycle forests in the Western United States, Avista has implemented an
effective strategy to reduce the potential for utility-caused wildfires.
As the Risk Tree Program matures, the inventory of risk trees
identified and removed should continue to reduce in numbers as long
as the goals and objectives remain in line with current standards. An
annual cycle is consistent with best-in-class programs at other major
utilities in the West.
Risk Tree Avista has taken a comprehensive approach to identify and mitigate
Strategy risk trees that pose a hazard to the overhead distribution system.
This approach has a two-fold benefit of reducing the volume of trees
that can potentially result in a utility-caused wildfire, as well as
reduce the types of tree-related events that cause interruption of
electrical service.
Identifying By leveraging the industry-accepted UAA/ISA guide, Best
Risk Trees Management Practices— Utility Risk Tree Assessment, Avista is
utilizing the most current protocols in use today by North American
Utilities to identify off-ROW risk trees that pose a hazard to the
electrical grid and potentially pose a wildfire risk.
Outage Avista should commit to studying the root causes of tree-related
Investigations outages through accurate reporting and thorough post-outage
investigations. A commitment to post-incident investigations does not
mean every outage needs to be investigated; however, the more
data, the better the analysis.
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Table of Contents
ExecutiveSummary ........................................................................................................2
Introduction ..................................................................................................................2
AssessmentProcess....................................................................................................2
KeyObservations......................................................................................................... 3
Avista Distribution Risk Tree Program............................................................................. 5
Wildfire Resiliency Plan................................................................................................ 5
FireRisk Profile............................................................................................................ 6
Risk Assessment Strategy........................................................................................... 8
Risk Tree Workload, Cost, and Tree Failure.............................................................. 10
IdentifyingRisk Trees............................................................................................. 10
Post-outage Investigations ..................................................................................... 12
Tree-related Outages................................................................................................. 13
Cycle Length and Objectives.................................................................................. 15
Historical Risk Tree Workload ................................................................................ 16
IISConsulting Team...................................................................................................... 18
AdamWarf................................................................................................................. 18
SteveHallmark........................................................................................................... 18
Dr. Phil Charlton......................................................................................................... 18
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Avista Distribution Risk Tree Program
Wildfire Resiliency Plan
Wildfires are generally defined as "unplanned, uncontrolled fires fueled by an area of
combustible vegetation" and, like all fires, require three fundamental elements to exist:
fuel, oxygen, and heat. The fuel supply across North America has increased over the
past few decades due to political policies around fire suppression and forest
management, the introduction of non-native grasses, and dryer climates and droughts
that left forests damaged by insects and disease. Oxygen often comes in the form of
high winds that can spread the fires quickly. Sparks that initiate the fires are primarily
generated by human activities and weather, but about 10% of wildfire ignitions are
sparked by faults in electrical infrastructure or electric equipment failure.' In recent
years, wildfires have emerged as a significant risk to public safety and to the bulk power
system (BPS) assets that serve the Western Interconnection of North America.
Wildfires initiated by electric utility infrastructure prompted the state of California to
enact legislation in 2018 that required each electrical corporation, local publicly owned
electric utility, and electrical cooperative to do two things: 1) construct, maintain, and
operate its electrical lines and equipment in a manner that will minimize the risk of
catastrophic wildfire posed by those electrical lines and equipment and 2) prepare and
submit wildfire mitigation plans (WMPs) on an annual basis for review and approval by
the California Public Utility Commission (CPUC).
Recognizing the value of WMPs, a significant number of electric utilities outside of
California in the Western US have voluntarily developed their own WMPs to identify and
reduce their wildfire risk exposure. Both investor-owned and publicly owned utilities
(e.g., municipal, cooperative, REA, and federal utilities) have developed WMPs as
guiding documents to codify their risk reduction efforts as they relate to wildfires.
Electric Utilities in the Western US with WMPs include:
• Bonneville Power
• Idaho Power
• Northwestern Energy
• PacifiCorp
• Puget Sound Energy
A WMP details a utility's initiatives and activities for reducing the risks of its lines and
equipment igniting wildfires in the high fire risk areas of its service territory. The risks
associated with the equipment vary depending upon several factors: age and condition,
population density (ingress and egress), surrounding climate, terrain and vegetation,
"Wildfire Mitigation Webinar Series." U.S. Department of Energy, Office of Electricity.April 2021.
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voltage class and type of construction, and policies and regulations around land/forest
management. New technologies and increasing data capture have enabled companies
to perform risk analyses at the asset level, allowing them to prioritize activities and
develop initiatives for specific lines and equipment. This granularity provides for more
effective and efficient mitigations.
While each utility's risks are unique, general metrics for various aspects of the plan
enable a utility to assess the outcomes and measure the performance of individual
initiatives. Identifying plan successes and deficiencies ensures that the iterative
development process is one of continuous improvement.
In general, WMPs describe how the utilities' electric systems are designed, constructed,
operated, inspected, and maintained to promote wildfire safety, prevention, mitigation,
and recovery.
Fire Risk Profile
As identified in the Wildfire Resiliency Plan, Avista has committed to reducing fire risk to
its communities, customers, and the company. Like other utility wildfire plans, Avista is
making investments in four key areas:
1. Grid Hardening — to invest in electric line infrastructure to reduce spark-ignition
outage events and protect critical assets from the impact of wildfires.
This has become a key focus of utilities that are exposed to the highest
probability of utility-caused wildfire ignitions, as well as protecting assets from
any wildfire that encroaches on the utility's assets. Some examples include
undergrounding, fire-resistant overhead construction materials (e.g. composite
poles, or fire-retardant wrapped material on poles), as well as the use of tree wire
and construction standards that reduce the failure potential of overhead lines.
2. Enhanced Vegetation Management — to inspect 100% of distribution line
assets annually and combine remote sensing technologies such as LiDAR and
satellite imagery to aid in overall vegetation management decision-making.
Annual inspections of overhead electrical facilities in high fire risk (or high fire
threat) areas of a utility's footprint are becoming commonplace, and in certain
states a regulatory requirement. Such inspections take place for infrastructure
(typically poles and hardware), as well as to identify hazardous trees.
3. Situational Awareness — to automate Avista's non-reclosing protection strategy
and align short-term, weather-related fire risk with system protection levels.
This is a basic tenet of a utility wildfire risk reduction effort. Seasonal adjustments
to reclosure settings are an accepted standard for many utilities in high fire risk
areas. Increasingly, remote switching at the sub-circuit level is being deployed to
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isolate electrical facilities damaged by wildfire, as well as proactive de-energizing
of line segments during high fire threat periods. It should be noted that proactive
de-energizing is a very complex process for any utility to deploy, and requires
significant buy-in among the utility, regulators, and customers.
As documented in Avista's Wildfire Resiliency Report:
"Avista has developed a computer algorithm to monitor, forecast, and adapt to
fire-weather events. Avista's Fire Weather Dashboard combines the National
Weather Service's 7-day forecast with Avista infrastructure data to quantify the
daily fire risk on 350 distribution circuits. This allows system operators to align
circuit protection settings with fire-weather conditions and minimize the potential
for spark-ignition on a circuit-by-circuit basis. This monitoring system is similar to
those used in California. In fact, Avista worked closely with San Diego Gas &
Electric to calibrate the system to achieve a balance between electric service
reliability and fire ignition potential. This monitoring system supports Avista's fire
season circuit protection program known internally as Dry Land Mode."
Observation: San Diego Gas & Electric (SDG&E) has been at the forefront of
managing wildfire risk and developed one of the most
comprehensive utility wildfire management programs in the United
States. Leveraging SDG&E's experience and knowledge is
commendable.
4. Emergency Response & Operation — to help customers be better prepared for
wildfires and partner with emergency first responders before, during, and after
fire events.
Emergency Response Plans are core to a utility's ability to effectively manage
the complexities of any emergency, including wildfire. By actively engaging local
and state agencies in the development and execution of a utility emergency
response plan, all parties involved can perform at their highest level. In turn, the
customers are best served with reliable information that keeps them informed
and able to make informed decisions.
These are core principles of a proactive Wildfire Mitigation Plan (WMP), which is the
term typically used by most electric utilities in the Western United States. These
principles provide focus for the utility on design and maintenance practices that can best
reduce the risk of utility-caused wildfires, as well as establish clear operating
procedures during periods of elevated wildfire potential. Avista has established a
framework for a plan to identify and reduce risk from wildfire on their system.
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Risk Assessment Strategy
For this report, IIS will focus specifically on the Risk Assessment Strategy as it relates to
the Distribution Risk Tree Program.
In 2019, Avista developed the initial wildland urban interface (WUI) map that combined
data from the Wildfire Hazard Potential with the location of Avista electric lines in areas
of low, medium, and high population. This analysis indicated that 3,240 miles of Avista's
7,725-mile distribution system were located in high fire threat districts (42% of the
system). Avista's 2020 Wildfire Plan focused on grid hardening and vegetation
programs in these elevated risk areas.
In 2023, Avista's WUI map was updated and now includes additional data which
measures the impact of fire on human development. The USDA's Housing Unit Impact
dataset14 combined with the Wildfire Hazard Potential data mentioned previously, was
used to refine the Avista WUI map. Areas shown on the 2023 WUI map with either an
orange or pink highlight indicate these high fire risk zones. Communities like Chewelah
and Colville border national forest lands, as do many other areas including Sandpoint,
St. Maries, Grangeville, and portions of the Lewiston/Clarkston Valley, placing them
more at risk. In total, 2,746 miles of electric distribution lines are in high fire risk areas or
about 36% of the system. This analysis indicates slightly lower risk values as compared
to 2019.
The WUI map serves to identify and prioritize the areas of highest risk. The Avista WUI
identifies three wildfire risk levels:
f-
Tier 1: Moderate levels of fuel and low to ^
moderate housing densities (low) �"C
Tier 2: Moderate to high levels of fuel
and moderate housing densities
(medium) R , �
A ^
Tier 3: High fuel levels and moderate to
high housing densities (high)
41
-wiston
s
Kennewick •
r+acna
n
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By overlaying the vegetation management polygons with the WUI map, the percentages
of the polygon with a tier 3 (highest risk), tier 2, and tier 1 WUI designation were
calculated. These percentages were then used to generate a risk score for each
vegetation management polygon. A weight was applied to each of the WUI tier levels to
ensure that tier 3 areas are placed at higher priority levels than WUI tiers with lower risk.
The following table demonstrates how the overall risk weighting score for Avista is
calculated on each vegetation management polygon.
Table 1. Weighting calculation example for risk tree prioritization
WUI Tier Weight applied Sample calculation CDA R P4 (WUI %) x weight
3 10 0.229 x 10 = 2.29
2 5 0.655 x 5 = 3.275
1 1 0.009 x 1 = 0.009
Overall risk score 5.574
In 2017, the California Public Utilities Commission adopted the CPUC Fire-Threat Map
which describes the boundaries of a new High Fire Threat District (HFTD) where utility
infrastructure and operations will have stricter fire-safety regulations. The CPUC Fire-
Threat Map incorporates the fire hazards associated with past powerline wildfires and
ranks fire-threat areas based on the risks that utility-associated wildfires pose to people
and property.
The main team that handled the development of the CPUC Fire-Threat Map was a
group of utility mapping experts known as the Peer Development Panel (PDP), with
oversight from a team of independent experts known as the Independent Review Team
(IRT). The members of the IRT were selected by CAL FIRE and CAL FIRE served as
the Chair of the IRT. The development of CPUC Fire-Threat Map includes input from
many stakeholders, including investor-owned and publicly-owned electric utilities,
communications infrastructure providers, public interest groups, and local public safety
agencies. Additional intormation on C;alitornia's approach can be tound at the CCalitornia
PUC Fire Safety Rulemaking Background webpage.
The process that Avista has utilized to define Risk Tiers is comparable to the California
approach utilized to delineate the High Fire Threat Districts.
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Risk Tree Workload, Cost, and Tree Failure
Identifying Risk Trees
Industry research has shown that the vast majority (80% or more) of tree-caused
outages are a result of trees or tree parts falling from off the ROW.
• On TransAlta's distribution system, where all overhangs were removed, 90-98%
of tree-caused outages were due to tree failure 2
• Niagara Mohawk reported 86% of tree-caused outages result from trees outside
the right-of-way 3
• Puget Sound Energy found 66% of all outages were caused by trees greater than
15 feet from the nearest conductor 4
• A survey of 71 utilities by the University of Wisconsin found about 81% of
outages are due to off-ROW trees, broken branches, and whole tree failures
rather than on-ROW grow-ins 5
Risk is the combination of the likelihood of an event and severity of the potential
consequences. The Utility Arborist Association developed, and the International Society
of Arboriculture published, the Utility Risk Tree Assessment best management practices
which aid in the development of this tool.
The likelihood a tree will cause an outage, damage utility infrastructure, or cause a
wildfire is dependent on the likelihood that a) the tree will fail and b) the failed tree will
impact the electrical system.
Table 2. Likelihood matrix presented in the UAA//SA Utility Risk Tree Assessment
Likelihood Likelihood of Impact on the System
of Failure Very low Low Medium High
Imminent Unlikely Somewhat likely Likely Very likely
Probable Unlikely Unlikely Somewhat likely Likely
Possible Unlikely Unlikely Unlikely Somewhat likely
Improbable Unlikely Unlikely Unlikely Unlikely
2 Guggenmoos, S. 1996. "Outage statistics as a basis for determining line clearance program status."
UAA Q. 5(1).
3 Finch, K.E., and C.Allen. 2001. "Understanding Tree-Caused Outages." EEI Natural Resource
Conference.Apr. 2001. Palm Springs, CA.
4 Rogers, B.I. 2001. "Puget Sound Energy Tree Watch Program." EEI Natural Resource Conference,Apr.
2001, Palm Springs, CA
5 "Utility Vegetation Management in North America," College of Natural Resources, University of
Wisconsin—Stevens Point, and CNUC. March 22, 2021.
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Tree risk rating is based on the likelihood of failure and impact combined with the
severity of the consequence of impact. The severity of consequence will differ for 69kV
vs 7.2kV, single- vs multi-phase lines, sections with and without special equipment, and
so forth. Following is a risk rating matrix which combines these factors.
Table 3. Risk Tree Rating Matrix presented in the UAA/1SA Utility Risk Tree Assessment
Likelihood of Consequence of Failure
Failure & Impact Negligible Minor Significant Severe
Imminent Low Moderate High Extreme
Probable Low Moderate High High
Possible Low Low Moderate Moderate
Improbable Low Low Low Low
The consequence assessment should reflect what portion of the system is involved
(e.g., 69kV, multi-phase, single-phase) and Wildfire Hazard Potential (WHP)
designation.
Observation: By leveraging the industry-accepted UAA/ISA guide, Best Management
Practices— Utility Risk Tree Assessment, Avista is utilizing the most
current protocol in use today by North American Utilities to identify off-
ROW risk trees that pose a hazard to the electrical grid and potentially
pose a wildfire risk.
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Post-outage Investigations
One of the greatest challenges facing UVM professionals is knowing which trees cause
outages and how. Utilities cannot effectively manage a problem they do not understand.
Not all tree species have the same failure rate. Not all portions of the system respond
the same to tree contact (1- vs 3-phase) and the consequence of failure varies widely
(e.g., 69kV vs 1-phase 7.2KV). Best Management Practices— Utility Risk Tree
Assessment provides general guidance regarding risk factors, but best practices utilities
collect utility-specific data through post-outage investigations. Utilities need to study the
root causes of their specific tree-related outages to replace intuition, anecdotal
evidence, and generalized industry data with reliable data.
The Avista VM team does not currently investigate tree-related interruptions. Utilities
that begin post-event investigation of tree-related outages initially find a 25-40% error
rate in unaudited reporting.
Observation: Avista should commit to studying the root causes of tree-related outages
through accurate reporting and thorough post-outage investigations. A
commitment to post-incident investigations does not mean every outage
needs to be investigated; however, the more data, the better the
analysis. Those selected for investigation should include incidents on all
voltages, construction types, and in both storm and non-storm situations.
They should also be timely—conducted close to the outage occurrence.
The objective of these investigations is to understand which trees fail, how they fail, and
how they impact the electrical system. These post-outage investigations should be
performed by an experienced arborist to:
• Give direct feedback on which trees are causing the majority of interruptions
• Provide learning opportunities for the arborist
• Refine assessment criteria
These investigations should go beyond simply indicating it was a "tree-related event" to
identifying distinct characteristics about the tree and the site surrounding it. The data
can then be used to drive the risk tree mitigation process. Data collected during post-
outage investigations often include:
• Voltage • Orientation to the line
• Line configuration (single-wire • Tree or tree part that failed
primary, 2-wire primary, etc.) . Nature of failure (trunk failure,
• Tree species branch failure, uprooted tree, etc.)
• Height • Condition of tree or tree part failure
• Diameter . Site conditions
• Distance to the line • Date of last maintenance
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Tree-related Outages
Since the full rollout of the Risk Tree Program, Avista has documented that more than
60% of the tree-related outages in Idaho from 2020 to 2023 occurred in Tiers 2 and 3.
Tree-related Outages by Tier
400
a
350
6 300
ca
250
0 200
150
= 100
z 50 ■
Tier 0 Tier 1 Tier 2 Tier 3
■2020 2021 2022 2023
Note: Although the WUI map identifies three wildfire risk levels, Avista also collects
outage data for Tier 0 (i.e., nominal risk with low levels of fuel).
Over the past ten years in Idaho, 92% of spark-related outage events fall into five basic
cause categories: animal, weather, public, tree, and equipment. Of these categories,
electric utilities can have the most influence over reducing equipment- and tree-related
events. Animal, weather, and public are much harder to predict and guard against.
Spark-related Outage Events (2014-2023)
Public
18%
Weather
8%
■ Equipment
54%
Tree
8%
■ Other
■ Animal 8%
4%
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As covered previously under the Fire Risk Profile section of this report, Avista has
identified Grid Hardening and Enhanced Vegetation Management as two of the four
areas for reducing wildfire risk on the company's electrical grid.
Additionally, research and industry data has shown the following:
1. Unless the distribution lines are entirely enveloped by vegetation, a shorter cycle
seldom results in fewer tree-related interruptions.6
2. At distribution voltages (15kV and below), trees in incidental contact are unlikely
to result in an electrical fault (phase-to-ground) causing an interruption.
• Tree grow-ins represent only 2-14% of all tree-caused outages.',$
• At voltage gradients below 2kV per foot, the probability of a fault occurring is
almost zero.9
3. Due to the above, almost all tree-related outages are caused by whole trees or
limbs falling on the conductors and creating a phase-to-phase electrical fault or
physical damage rather than by tree growth resulting in incidental contact with
the lines.10
Observation: Avista has taken a comprehensive approach to identify and mitigate risk
trees that pose a hazard to the overhead distribution system. This
approach has a two-fold benefit by reducing the volume of trees that can
potentially result in a utility-caused wildfire, as well as reduce the types
of tree-related events that cause interruption of electrical service.
6 Guggenmoos, S. 1996. "Outage statistics as a basis for determining line clearance program status."
UAA Q. 5(1).
Rees, W.T., Jr., T.C. Birx, D.L. Neal, C.J. Summerson, F.L. Tiburzi, Jr., and J.A. Thurber. 1994. "Priority
Trimming to Improve Reliability." ISA conference presentation, Halifax, NS.
8 Finch, K.E., and C. Allen. 2001. "Understanding Tree-Caused Outages." EEI Natural Resource
Conference.Apr. 2001. Palm Springs, CA.
9 Russell, D. et. al. 2011. "Best Practices in Vegetation Management for Enhancing Electric Service in
Texas." PUCT Project 38257.
10 Guggenmoos, S. 2003. "Effects of Tree Mortality on Power Line Security." Arboriculture & Urban
Forestry, 181-196.
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Cycle Length and Objectives
As currently designed and implemented, Avista's Enhanced Vegetation Management
Program incorporates two primary components relative to management of vegetation on
the overhead distribution system: Routine and Risk Tree.
The Routine Maintenance Program emphasizes maintaining a five-year cycle for
addressing the vegetation on the entire distribution system and preventing grow-in
outages. To meet these objectives, the routine maintenance program prioritizes work
based on time since last trim and number of grow-in related outages.
The Risk Tree Program objective is to identify risk trees, with the potential of imminent
fall-in or grow-in hazard to the energized facilities, and ensure they are trimmed or
removed to eliminate potential for fire ignitions and outages. A risk tree is defined as
visibly dead, diseased, dying, or possessing obvious structural defects that could fall
into the conductor. The corresponding risk tree annual patrol identifies trees which are
deemed a threat to reliability and pose a fire risk.
The Routine Maintenance Program and Risk Tree Program are interrelated because
risk inspections and mitigation are performed as part of routine maintenance if a
polygon is on the routine plan for the year. This allows for planning and mitigation work
to happen using the same planners and crews. While the Risk Tree Program and
Routine Maintenance work planning and mitigation contracts are separate, this enables
Avista to move crews between programs as needed to meet work plan objectives and
gain efficiencies.
Observation: Implementing an extensive risk tree assessment and mitigation program
is a best practice today. This includes documenting the root cause of
outages (e.g., which trees/conditions result in failure) and aggressively
targeting higher risk, off-ROW trees (see previous reference).
Important to note: The optimum cycle for preventing tree growth into the conductors
may be different from the optimum cycle for off-ROW risk tree mitigation.
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Historical Risk Tree Workload
Beginning in 2020 when Avista implemented the system-wide patrol of the overhead
distribution system, the annual volume of risk trees abated has increased year-over-
year. Expenditures had initially shown an annual cost per tree increase for 2020-22, but
a reduction in cost per tree in 2023.
Idaho Risk Tree Expenditures
16000 $600
14000 $500
'0 12000
a) 10000 $400
fy
8000 $300
a� V)
6000 $200 v
n 4000
121� 2000 $100
0 $0
2020 2021 2022 2023
Total Risk Trees Completed Cost/Risk Tree
Contributing factors include:
• More than 90% of the U.S. West was in moderate drought or worse by late June
2021. More than a quarter was in exceptional drought, the highest level,
indicating widespread risk of crop loss, fire, and water shortages."
Moderate drought or worse Severe drought or worse —Extreme drought or worse —Exceptional drought
IuC'
80
60
40
20
0 A . , - AAL .A
2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020
Data as of June 24,2021
Chart:The Conversation!r -BY-ND-C:_urcr r,n_i,hAcrito,-�,nt-r,dsta
11 "National Drought Highlights Report," U.S. Drought Monitor, June 24, 2001.
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Distribution Risk Tree Program Assessment for Avista Utilities
• Trees in Western forests have been dying at an alarming rate over the past two
decades due to droughts, high temperatures, pests, and fires.12
• Labor cost and availability has had a significant impact on utilities. Based upon
Avista's experience in 2022, the increased volume of risk trees required
mobilization of crews from outside the region to accomplish the workload.
Conversely, by achieving a stabilized workforce in 2023, per unit costs
decreased by 17%.
To determine if a program is influencing system performance, one of the most valuable
measures for a risk tree program is to show a reduction in the occurrence of actual tree
fall-ins. For the evaluation period from 2020 to 2023, Avista has recognized a 62%
reduction in tree fall-ins.
Idaho Tree Events by Outage Type
350
300
v, 250
c
> 200
w
m 150
100
50
0
2020 2021 2022 2023
■Tree Fall-In ■Tree Grow-in
Observation: Considering the impact that drought and tree mortality has had on
forests in the western United States, Avista has implemented an
effective strategy to reduce the potential for utility caused wildfires. By
maintaining the current annual cycle of identifying and abatement of risk
trees, the inventory of risk trees identified and removed should continue
to reduce in numbers so long as the goals and objectives remain
consistent with current practices. By doing so, the annual cycle should
continue to reduce the overall risk exposure from hazard trees.
12 Daniel Johnson and Raquel Partelli Feltrin, "Trees are dying of thirst in the Western drought,"
The Conversation, June 29, 2021.
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IIS Consulting Team
Adam Warf
Mr. Wares experience includes leading business development strategies for a
`, Q r utility vegetation management consulting firm, vegetation management field
operations at two major investor-owned utilities in the southeastern US,
project management at a variety of utilities in the mid-Atlantic and southeastern regions,
and vegetation management program development and assessments across the
country. His utility arboricultural experience provides a broad understanding of the many
different methods used to create a successful utility right-of-way vegetation
management program, including remote sensing, work management solutions, data
analytics, optimization, and the utilization of third-party consulting foresters for planning
and auditing duties.
Steve Hallmark
Mr. Hallmark serves in a senior leadership role to IIS' Chief Operating Officer,
driving strategic solutions, innovation, and an entrepreneurial vision to power
and energy companies. Mr. Hallmark has extensive experience managing
large-scale utility vegetation management programs, including budget, regulatory
compliance, and contract design and enforcement. Over the years, he has served in a
leadership capacity on vegetation management issues and acted as a government and
industry liaison. Most recently, he served as part of a team at the direction of the
California Governor's Office overseeing PG&E's Wildfire Mitigation Program. With over
40 years of utility vegetation management and line construction practices experience,
Mr. Hallmark is recognized as a highly qualified subject matter expert on a national
level.
Dr. Phil Charlton
,0 Dr. Charlton has worked with over 150 electric utilities in seven countries,
helping to develop long-term vegetation management programs for distribution
W line clearance and transmission rights-of-way maintenance. Most of these
studies required detailed evaluation of the vegetation conditions, work practices, and
operating procedures. Dr. Charlton has also been active in industry research since
1980. His research has encompassed cost and effectiveness issues related to rights-of-
way maintenance, environmental concerns with use of herbicides, wetlands protection,
reliability, and more.
Page 18 of 18

-
Wildfire
Mitigation
Flan
fi

Avista Corporation 2026 Wildfire Public Safety Power Shutoff Plan
Statement from Avista Executive Management
2025 represents Avista's 2nd year of implementing the Public Safety Power Shutoff (PSPS) Plan. This
Plan adds to the work being done to minimize risk of wildfire in Avista's 2026 Wildfire Mitigation Plan.
The framework for operational izing a PSPS Plan at Avista is firmly rooted in our 135-year operating
history and represents the collective knowledge of Avista employees and fire agency professionals
together with assistance from peer utilities, and most importantly, engagement with customers. It also
reflects our commitment to partner with customers, communities, and those who manage forest
landscapes and fight fires.
We all have a role to play in minimizing the risk of wildfire.
Heather Rosentrater,President and Chief Executive Officer(CEO)
Date: 11-20-2025
Wayne Manuel, Senior Vice President, Operations and echnology
LA-)C.1�
Date: 11-20-2025
Josh DiLuciano, Vice President Energy Delivery
Date: 11-20-2025
Eliza/eth Frederiksen, Director of System Operations
j � Date: 11-20-2025
Matt Ugaldea, Manager of Wildfire Resiliency Program
ye
���� Date: 11-20-2025

Avista Corporation 2026 Wildfire Public Safety Power Shutoff Plan
Document Owner: The Wildfire Resiliency team is responsible for maintaining this document.
This includes coordinating with Emergency Management in scheduling annual reviews and
exercises, updating content based on annual reviews and exercises, and redistributing new
versions of the document to stakeholders.
The plan will be reviewed and exercised annually. The scale of the exercise will be determined
by the Wildfire Executive Committee in coordination with Wildfire Resiliency personnel and key
leadership.

TABLE OF CONTENTS
Tableof Contents ............................................................................................................ 1
Listof Figures..................................................................................................................3
1. Introduction ................................................................................................................................4
2.Acronyms.....................................................................................................................5
3. Public Safety Power Shutoff Overview.........................................................................6
4. Purpose & Scope.........................................................................................................6
5. PSPS Risk-Informed Decision Making.........................................................................7
5.1.Wildfire Risk.........................................................................................................7
5.1.1. PSPS Feeders & Circuits...........................................................................7
5.2. PSPS Weather Monitoring and Review ............................................................. 12
5.2.1. Fire Risk Index......................................................................................... 12
5.2.2. National Weather Service Red Flag Warning........................................... 13
5.2.3. Agency Input............................................................................................ 14
6. PSPS Operations..................................................................................................... 14
6.1. General .............................................................................................................. 14
6.2. Decision Process for PSPS ............................................................................... 14
6.3. Event Response & Management ....................................................................... 14
6.4. De-energization Protocols.................................................................................. 16
6.5.Wildfire Encroachment and Proactive De-energization of Transmission Lines ..16
6.6. PSPS Recovery (Monitor, Patrol, Restore)........................................................20
7. Roles & Responsibilities ............................................................................................22
7.1. Electric Field Operations....................................................................................22
7.2. Electric Distributions Operations........................................................................22
7.3. Director of Electrical Engineering.......................................................................22
1

7.4.Wildfire Resiliency..............................................................................................22
7.5. Corporate Communications ...............................................................................23
7.6. Customer Service .............................................................................................23
7.7. Business and Public Affairs ..............................................................................23
7.8.Supply Chain Management................................................................................24
7.9. Fleet Management.............................................................................................24
7.10.Substation Operations......................................................................................24
7.11.Vegetation Management..................................................................................24
7.12. Products and Services .....................................................................................24
7.13.Geographic Information Systems.....................................................................25
7.14. Executive Officers ............................................................................................25
7.15. Legal ................................................................................................................25
7.16. Regulatory........................................................................................................25
7.17. Emergency Management ................................................................................26
7.18. Finance ............................................................................................................26
8. Community Outreach & Preparedness.....................................................................26
8.1. Coordination with Public Safety Partners and Municipalities .............................26
8.2. Community Support...........................................................................................26
8.3. Proactive Customer Communications................................................................29
8.4. Information Sharing............................................................................................29
9. Continuous Improvement......................................................................................... 30
10. Financial Administration ........................................................................................... 30
11. Reporting.................................................................................................................. 30
12.After-Action Report................................................................................................... 30
13.Training ....................................................................................................................31
14.Exercises ................................................................................................................. 31
2

List of Figures
Figure 1
PSPS Top 25 Avista Wildfire Risk Feeders Map.............................................................................................8
Figure 2
PSPS Spokane & Coeur d/Alene Risk Feeders Map......................................................................................9
Figure 3
PSPS Sandpoint & Kellogg Risk Feeders Map............................................................................................. 10
Figure 4
PSPS Grangeville Risk Feeders Map............................................................................................................ 11
Figure 5
Organizational Process Flow......................................................................................................................... 16
Figure 6
RestorationProcess ...................................................................................................................................... 18
Figure 7
CommunicationTimeline...............................................................................................................................25
Appendix A: Notification Plan
3

1 . INTRODUCTION
In the Northwest, the number, size, and severity of wildfires have increased in recent years.
This trend is expected to continue as temperatures rise, and drought persists'. Avista
published its first Wildfire Resiliency Plan in June of 2020, which introduced the risks, costs,
and benefits of implementing a holistic set of measures to reduce utility wildfire risk. The 2020
Plan built upon Avista's operating history responding to and mitigating for wildfire activity in
addition to adopting other risk mitigation strategies employed by peer utilities. Avista updated
its Wildfire Mitigation Plan in 2025 which incorporates updates to existing mitigation efforts,
introduces new strategies, and reinforces Avista's ongoing commitment to minimizing wildfire
risk for its communities, customers, and infrastructure.
Similar to other utility wildfire mitigation plans, Avista is making investments in four key areas:
Grid Hardening — investing in electric infrastructure to reduce spark ignition outage
events and to protect critical assets from the impact of wildfires.
Enhanced Vegetation Management — reducing the number of vegetation-related
issues that can lead to outages and/or spark events by inspecting our powerline assets
in high-risk areas to identify and mitigate risk trees. Adding remote sensing technologies
such as LiDAR and satellite imagery to enhance overall vegetation management
information and decision-making.
Situational Awareness — providing both static and dynamic tools needed to identify
and response to wildfire risk.
Operations & Emergency Response —preparing for and effectively reacting to wildfire
situations, including operational tactics during a wildfire situation as well as training and
collaborating with critical partners in managing wildfire events in a holistic, unified way
to protect our customers and communities.
As part of its operational mitigation strategies, Avista has developed this Public Safety Power
Shutoff Plan (PSPS Plan or Plan) to guide the assessment and decision making process when
determining to proactively de-energize electrical facilities in identified areas of extreme wildfire
risk when conditions make the wildfire risk so severe it is deemed more unsafe to operate our
electrical facilities than the reliability risk of de-energizing. Proactive de-energization reduces
the potential of electrical facilities to become a wildfire ignition source if there is a fault or
creating safety concerns for not only our customers and communities but first responders and
Avista staff as well.
1 USDA Climate Hub,"Climate Change and Wildfire in Idaho,Oregon,and Washington,"https://www.climatehubs.usda.gov/hubs/northwesUtopic/climate-change-and-wildfire-idaho-oregon-and-
washington
4

2. ACRONYMS
AAR — After Action Review
AE —Account Executive
CEO—Chief Executive Officer
CRC — Community Resource Center
DNR — Department of Natural Resources
DOT — Department of Transportation
EM — Emergency Management
EOC — Emergency Operations Center
EOP — Emergency Operations Plan
ERT — Estimated Restoration Time
EWC — Executive Wildfire Committee
FRI — Fire Risk Index
FSM — Fire Safety Model
FWW —Fire Weather Watch
GIS — Geographic Information System
ICS — Incident Command Structure
IPUC — Idaho Public Utility Commission
IVR — Interactive Voice Response
NWS — National Weather Service
OEM — Office of Emergency Management
PG&E — Pacific Gas & Electric
PSPS — Public Safety Power Shutoff
PUC — Public Utilities Commission
RBM — Regional Business Manager
RFW—National Weather Service issued Red Flag Warning
WRMAA— Western Region Mutual Assistance Agreement
WUTC — Washington Utility and Transportation Commission
Formerly known as Dry Land Mode(DLM)
5

3. PUBLIC SAFETY POWER SHUTOFF OVERVIEW
Over the last several decades, the western United States (U.S.) has experienced an increase
in the intensity of wildland fires (wildfires). There have been several factors contributing to this
trend, including climate change, increased human encroachment in wildland areas, historical
land management practices and changes in forest health. Recent events in western states
have increased awareness of electric utilities' role in wildfire prevention and mitigation.
Avista has always prioritized keeping our communities and customers safe and continues to do
so by increasing the resilience of Avista's transmission and distribution (T&D) facilities. As part
of its wildfire mitigation operations, Avista developed this PSPS Plan to proactively shut off
power to electrical facilities during extreme weather events when the risk of wildfire outweighs
the reliability concerns of de-energizing. Based on the inherently disruptive nature of power
outages, PSPS events must be carefully evaluated under this Plan to balance wildfire risk with
reliability risk, understanding the potential impacts a PSPS would have on Avista customers
and the communities it serves. For Avista, proactive de-energization is a measure of last resort
to reduce wildfire risk.
4. PURPOSE & SCOPE
This PSPS Plan identifies relevant considerations, decision process flow and implementation
protocols before, during and after a PSPS event. The Plan will be active during wildfire season
(typically May — October) and reviewed and updated annually as necessary prior to the start of
the next wildfire season.
Nothing in this Plan supersedes the general authority of Avista to de-energize a power line
during an emergency, and a decision (i.e., to protect fire response personnel or to protect
company assets from fire damage) might be made without complying with the notification and
outreach sections of this Plan. In addition, extreme weather events are, by their nature,
unpredictable and unique, so the specific considerations applicable to any decision regarding
possible de-energization may vary based on the specific circumstances.
The key goals Avista considers for the foundation of the Plan are listed below:
• Advancing the safety of customers, communities, first responders and Avista
employees
• Collaborating with key external stakeholders (agencies, counties, local governments,
public safety partners, tribes and first responders)
• Minimizing both potential wildfire risk and power outage impacts on communities and
customers
• Maintaining reliable electric service
6

5. PSPS RISK-INFORMED DECISION MAKING
5.1 . Wildfire Risk
Avista's 2019 Wildland Urban Interface (WUI) map combined data from the Wildfire Hazard
Potential with the location of Avista electric lines in areas of low, medium, and high population.
In 2023, Avista's WUI map was updated and now includes additional data which measures the
impact of fire on human development. The USDA's Housing Unit Impact Dataset-14 combined
with the Wildfire Hazard Potential data mentioned previously, was used to refine the Avista
WUI map. Communities such as Chewelah and Colville border national forest lands, as do
many other areas including Sandpoint, St. Maries, Grangeville, and portions of the
Lewiston/Clarkston Valley, placing them at higher risk. Spokane County, having seen
significant population growth, has an increasing number of housing developments within high
fire threat areas, increasing the risk of wildfire impacts. According to the updated data, 2,746
miles of electric distribution lines are in high fire risk areas, or about 36% of the system.
Although this analysis indicates slightly lower risk values compared to 2019, it still
demonstrates significant fire risk potential throughout the service territory.
5.1.1. PSPS Feeders & Circuits
In 2023, Avista developed a list of 25 distribution feeders with the highest likelihood of being
included in a PSPS event (the Top 25 List); this list was developed using the existing Avista
Fire Weather Dashboard, wildfire data, historic outage data and scenario planning. This Top
25 List was developed as part of Avista's risk-based approach to preparedness. The Top 25
List assists with the planning and preparedness process to support our customers in the
event of a PSPS event; the list does not preclude Avista from initiating a PSPS on other
feeders or circuits in its service territory. The maps below include those feeders where a
PSPS event is most likely to occur:
7

Top 25 Avista Wildfire Risk Feeders
I`
Feeder Names
- BLU322 LIB12F3
BUN424 LTF34F1
CKF711 MEA12F2
DAL133 ORO1281
FOR12F1 OSB521
GLN12F2 RAT233
GRN12F3 SAG741
GRV1271 SAG742
GRV1273 SE12F2
KAM1291 SE12F4
KAM1292 SUN12F2
KAM1293 WAK12F2
KOO1298 WEI1289
KOO1299
P
Miles
0 5 10 20 30 40
Figure 1
PSPS Top 25 Avista Wildfire Risk Feeders Map
8

Avista Wildfire Risk Feeders
in Spokane, Washington
and Coeur d'Alene, Idaho Areas
Tr.mwmd
A-D-AWAP
Mrwry 5 okan. �^""iro «.ay.
D.van N.1 t.
M.&-I Lk-
Feeder Names
BLU322 RAT233
DAL133 SAG742
FOR12F1 SE121F2
GLN12F2 SE121F4
LIB12F3 SUN12F2
LTF34F1 WAK12F2
MEA12F2
N
Miles
0 5 10 20 30 40
Figure 2
PSPS Spokane & Coeur d/Alene Risk Feeders Map
9

Avista Wildfire Risk Feeders
in Sandpoint, Idaho and Surrounding Areas
Feeder Names
CKF711 SAG i 42
SAG741
N
Miles
0 1.5 3 6 9 12
Avista Wildfire Risk Feeders
in Kellogg , Idaho and Surrounding Areas
c..�min. pmelxuv
Feeder Names
BUN424
OSB521
N
Miles
0 1.5 3 6 9 12
Figure 3
PSPS Sandpoint & Kellogg Risk Feeders Map
10

Avista Wildfire Risk Feeders
in Grangeville, Idaho and Surrounding Area
Feeder Names
GRV1271 KOO1298
GRV1273 KOO1299
KAM1291 ORO1281
KAM1292 WE11289
KAM 1293
N
Miles
0 5 10 20 30 40
Figure 4
PSPS Grangeville Risk Feeders Map
11

5.2. PSPS Weather Monitoring and Review
As a general matter, Avista would initiate a PSPS at specific locations if the Company
determines, based on the circumstances and information available at the time, that a
combination of critical conditions creates a consequential risk of wildfire ignition, as well as
spread, with the potential for severe impact, and that those risks outweigh the corresponding
risks associated with initiating the PSPS.
5.2.1. Fire Risk Index (FRI)
Avista developed a Fire Risk Index (FRI) to support short-term forecasting of wildfire threat
across its service areas. The FRI integrates multiple data sources—including weather
conditions, fuel types (shrubs, trees, grasses), topography, community risk, historic summer
outages, Severe Fire Danger Index, Fire Preparedness, and the percentage of overhead
spans in treed areas—into a single numerical score ranging from 0 to 9.
• 0 represents very green, wet fuels with low wind and high humidity
• 9 represents very dry fuels (live and dead), low humidity, and extreme wind speeds
These scores are grouped into five index levels:
1. Green (Low) — FRI 0-4.0: Fire spread possible, minimal outage risk
2. Blue (Moderate) — FRI 4.1-5.4: Mixed risk profiles for outage and fire spread
3. Yellow (High) — FRI 5.5-6.4: Elevated risk of outage and/or fire spread
4. Orange (Very High) — FRI 6.5-6.9: Very high risk of outage and fire spread
5. Red (Extreme) — FRI >_7.0: Extreme risk of both outage and fire spread
The FRI has been used to guide operational decisions, including the consideration of Public
Safety Power Shutoffs (PSPS) when the FRI reaches 7.0 or higher, alongside other situational
factors.
Note: While the FRI has played a key role in wildfire risk assessment for the 2024 and 2025
seasons, Avista is evolving its methodology and will transition to a similar, but new approach in
2026 for PSPS decision making. The FRI will not be used in the same capacity next year, and
the next version of this Plan will reflect updated tools and strategies to assess and respond to
wildfire risk.
5.2.2. National Weather Service Red Flag Warning
A Red Flag Warning (RFW) is a forecast warning issued by the National Weather Service
(NWS) to inform the public, firefighters and land management agencies that
conditions are ideal for wildland fire combustion and rapid spread. RFWs are often
12

preceded by a Fire Weather Watch (FWW), which indicates weather conditions that
could occur in the next 12-72 hours resulting in a Red Flag Warning.
The NWS has developed different zones across the nation for providing weather alerts
(such as RFWs) to more discrete areas. These zones are shown on this NWS
webpage: Fire Weather.
The following thresholds are used by most NWS offices:
Daytime:
• Relative humidity of 25% or less
• Sustained winds greater than or equal to 10 miles per hour (mph) with gusts
greater than or equal to 20 mph over a four-hour period
Nighttime:
• Relative humidity of 35% or less
• Sustained winds greater than or equal to 15 mph with gusts greater than or equal to 25
mph over a three-hour period
Lightning:
• The NWS rarely issues RFWs for lightning in the western United States. For this to occur,
the Lightning Activity Level—a measure of lightning potential specifically as it relates to
wildfire risk—needs to be at 3 or higher.
Although Red Flag Warnings are used as a tool for forecasting, they are only one factor
Avista considers when determining initiation of a PSPS event. Initiating a PSPS will
require a refined and focused approach for specific feeders rather than an entire
geographic area; consequently, a RFW cannot be used as the sole determinative
factor in whether to initiate a PSPS in any specific region or area.
5.2.3. Agency Input
Coordination with agencies like the Washington State Department of Natural Resources (DNR)
and Idaho Department of Lands (IDL) will also aid in the decision making for PSPS events.
During wildfire season, DNR provides weekly briefings which assist in analyzing drought
conditions and weather forecasts. IDL also holds meetings during wildfire season to provide
updates on wildfires and weather conditions.
13

6. PSPS OPERATIONS
6.1 . General
PSPS preparedness is a cyclical effort involving Avista, public safety partners, state and local
governments, communities and customers. The Director of Wildfire Resiliency along with the
Manager of Wildfire Resiliency coordinate and facilitate activities of multiple Avista business
units for wildfire prevention and mitigation activities while Business & Public Affairs, Customer
Solutions and Corporate Communications facilitate public outreach and coordination efforts
with external stakeholders.
6.2. Decision Process for PSPS
The weather monitoring and situational awareness criteria outlined in Chapter 5, in addition to
other factors mentioned, will assist Avista in determining whether a PSPS event may be
warranted. The decision to initiate a PSPS in any given situation based on the best available
information at the time, will come from final approval from a team of executives acting on
recommendations provided by the assessment team.
6.3. Event Response & Management
Avista will transition to PSPS Watch approximately 7-2 days prior to a potential PSPS event at
the direction of the Director of Wildfire Resiliency (Wildfire Lead). During the PSPS Watch
phase, Avista will activate the PSPS Assessment Team, which includes directors (or
delegates) from business units across the company. The PSPS Assessment Team will meet
as needed to discuss current and forecasted weather conditions and other critical information
regarding a potential PSPS event. The Director of Wildfire Resiliency will facilitate the PSPS
Assessment Team meetings and conference calls to ensure operational readiness for a
potential event. The Director of Wildfire Resiliency and Manager of Wildfire Resiliency will
provide a recommendation to the Wildfire Executive Committee taking into account input from
the PSPS Assessment Team. The Director of Wildfire Resiliency will determine whether to
remain at a PSPS Watch, escalate to PSPS Warning, or de-escalate to seasonal FSM
operations. The PSPS Assessment Team will decide if Avista will issue a preliminary
notification of a potential PSPS event to public safety partners and critical facilities operators.
The first notification to governmental agencies and emergency management partners could
occur during the 7-2 day PSPS Watch phase.
An Emergency Operating Plan (EOP) briefing will be initiated as early as 7 days prior to the
initiation of a PSPS Event. The Director of Electric Operations will aid in the coordination of the
PSPS event in close collaboration with the Director of Wildfire Resiliency (Wildfire Lead). See
Figure 5 for organizational process flow and transition into the EOP event. The procedures and
incident management structure outlined in the most current edition of the Avista Emergency
Operations Plan will be followed to coordinate the recovery from a PSPS event.
14

During PSPS Watch, the PSPS Assessment Team will review the PSPS Plan and supporting
documents. An operational risk assessment will be performed as well to determine risks and
vulnerabilities. A determination will be made whether to escalate to PSPS Warning by the
Director of Wildfire Resiliency approximately 48-24 hours in advance of a potential event.
Within one hour of initiating a PSPS Warning notification, the full PSPS team will be placed on
stand-by and team member availability will be determined. The full PSPS team is the PSPS
Assessment Team plus the Wildfire Executive
FF Cor'porate
PSPS Assessment 40MM Communications Execute
Director of � lDirector .
Wildfire Electric
Resiliency Operations
.. . Area Manager
SupplyWAsset
SupportPSPS Assessment
Business and Committee Customer
Public Affairs I � Service
Community Electric
Outrea Operations
Corporate Substation Vegetation
Communications Customer Service Operations Management
System Emergency
OperationsManagement
Products
Services
Figure 5
Organizational Process Flow
6.4. De-energization Protocols
Distribution Operations will develop the switching plan(s) to support PSPS execution once the
decision has been made to initiate a PSPS event. A final review of the switching plans by the
Director of System Operations will be completed prior to any PSPS execution. After the final
approval to activate PSPS is received, the Director of Electric Operations will work with the
appropriate District Operations Manager(s) to execute de-energization protocols.
15

6.5. Proactive De-energization of Transmission Lines
For the 2025 wildfire season, Avista added consideration of non-reclosing protection schemes
as well as de-energization, of 115kV transmission lines in certain situations. Avista's
transmission system is key to system reliability, and many factors will need to be considered in
decision making regarding transmission lines, just as is done on the distribution system.
Further analysis will be done regarding 230kV transmission lines. Although Avista is not
expecting to proactively de-energize 230kV transmission lines, the same situational awareness
of the risk and the impacts will be done for all transmission lines.
Decision-Making Process
Decisions related to transmission line de-energization and re-energization will be made by the
Wildfire Executive Steering Committee, as well as the Director of System Operations and
the Chief System Operator. Additional stakeholders will be included as appropriate.
System Operators will provide input, feedback, and concerns regarding available options
and their impacts.
Factors that will be considered in the decision-making process may include, but is not limited
to, the following:
- Fire Risk Index
- Impact on reliability from taking line out (outages, dropping load, curtailment, etc.)
- Location of transmission line(s)
- Predicted future weather forecast
- Historical performance/outages of transmission line
- Impact on neighboring utilities
Once a decision is made regarding de-energizing a transmission line or not, the rationale
should be documented.
Fire Rating Index (FRI)
The Fire Risk Index described earlier in Section 5.2.1 is the same scoring ranges, color
categories, and risk definitions that will be used to assess both transmission lines and
distribution lines.
6.6. PSPS Recovery (Monitor, Patrol, Restore)
Power restoration following a PSPS is similar to restoration after a major storm. In traditional
storm restoration efforts, the priority is to restore service to as many customers as possible
through line switching and by isolating faulted circuits. Restoration efforts may also include
consideration of customers most heavily impacted by outages or located in Named
Communities.
16

One of the significant differences from restoration after a major storm versus a PSPS, is the
process of patrolling. If a utility de-energizes lines for a PSPS event, facilities cannot be re-
energized until all circuits and lines are thoroughly patrolled, because when the line is de-
energized, there is no way to know if damage occurred on the line or not. After patrolling, lines
are re-energized segment by segment. Patrol of all impacted overhead electric facilities, both
transmission and distribution, can only commence once the weather event has subsided.
Restoration efforts following a PSPS will always require additional time to fully patrol each
circuit, to verify whether there was damage during the weather event.
Ll
J- ...
Line Patrol: Restore Power. Complete Repairs: Event Ends:
"All Clear"is declared by Start with Critical Main Trunk Lines •'is Declared Over
Updatedecision-makers Infrastructure,Commercial Branch Lateral Circuits After Action Review With
Field Crews Mobilized Zones with Equity Individual Customers Emergency V Responders
Broad Communications to Considerations .
Customers Including Help Communicate Estimated Estimated Restoration Time Thank You to Crews&
With Support Resources Restoration Time to to All Customers
Customers
Figure 6
Restoration Process
Restoration Process
One element of the PSPS restoration plan includes pre-staging two-person crews at known
PSPS facility locations when conditions allow, since these locations are identified in advance
of the event. The plan also accounts for the potential need to assign additional resources to
impacted transmission and distribution lines outside of the PSPS areas. Patrol activities begin
once an all-clear is issued. The timing of patrol completion depends on several factors,
including the extent of system damage, crew availability, and the ability to conduct aerial
patrols, which may be limited by weather conditions.
In scenarios where multiple circuits are affected, Avista may consider initiating a mutual
assistance request from other utilities and engaging outside contractors to support restoration.
The availability and location of these additional resources can influence restoration timelines.
As Avista further develops and refines its restoration efforts, specifically after the occurrence of
17

a PSPS, Avista will need to prioritize balancing and allocating additional resources to circuits
that may have been impacted by storm damage in Named Communities, in areas with critical
customers, and in areas with large numbers of customers. This will help ensure that restoration
efforts are equitable for the most vulnerable and highly impacted customers that may not have
equal means or access to resources during prolonged outages. This additional effort will take
more time and resources during the restoration process but ensures that equity is being
applied to the PSPS restoration process.
18

7. ROLES & RESPONSIBILITIES
Electric Field Operations
• Work closely with PSPS Assessment Team on field conditions and Estimated
Restoration Times (ERTs).
• Participate in After-Action Reviews (AARs) (further discussed in Section 12 below)
and ensure modifications to PSPS protocols are implemented as necessary.
Electric Distribution Operations
• Develop and implement safe and reliable power shutoff protocols and procedures.
• Ensure System Operators and Distribution Operators are appropriately trained to
perform relevant responsibilities under this PSPS Plan, and that such employees
receive timely information regarding wildfire risk and weather conditions for
purposes of performing those responsibilities in the event of a PSPS.
• Participate in the PSPS Assessment Team with PSPS evaluation and decision-
making.
• Safely restore service to PSPS areas when notified by Electric Field Operations
that patrolling has been completed as well as any needed repairs.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Director of Wildfire Resiliency
• Serves as the Wildfire Lead
• Activate the PSPS Assessment Team if a PSPS is likely.
• Support EOP Lead in facilitating PSPS event.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Wildfire Resiliency
• Oversee wildfire mitigation program (including this Plan) and support cross
departmental collaboration.
• Monitor daily, weekly and long-term weather and wildfire forecasts.
• Monitor weather conditions for Fire Weather Watches, Red Flag Warnings and
High Wind Watches and Warnings.
• Communicate with Washington Department of Natural Resources (DNR) and Idaho
Department of Lands (IDL).
19

• Oversee operation of the Customer Resource Centers and designated contractor
prior to and during PSPS event.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Corporate Communications
• Work directly with the PSPS Assessment team to create external messages to
share with stakeholders and customers regarding PSPS events.
• Implement its developed Notifications Plan to notify customers and employees on a
wide range of channels and in coordination with Avista's Customer Service and
Community Outreach teams. See appendix A: PSPS Notification Plan for additional
details.
• Participate in AARs and ensure modifications to PSPS protocols and
communication practices are modified as necessary.
• Ensure a coordinated and cohesive external and internal communication and
notification plan is in place and reviewed annually.
Customer Service
• Respond to customer calls and respond to questions with information provided by
Corporate Communications.
• Ensure customer service representatives are trained to manage customer
interactions during a PSPS event.
• CARES Team will provide additional communications to Life Support customers
managed under their case load.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Business and Public Affairs
• Communicate with external partners, governmental agencies, public safety
partners and critical business customers on updates and status regarding PSPS
watches, PSPS warnings, activity and following a PSPS outage.
• Coordinate internally with Corporate Communications and Wildfire Executive
Committee to ensure consistent communications with external partners and
customers.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
20

Supply Chain Management
• Ensure contract resources are appropriately trained to perform all relevant
responsibilities under this PSPS Plan.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Fleet Management
• Ensure employees are appropriately trained to perform all relevant responsibilities
under this PSPS Plan.
• Ensure readiness of resource pool equipment for a PSPS event.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Substation Operations
• Monitor substations and perform actions to support PSPS operations.
• Coordinate activities with Dispatch and Customer Service.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Vegetation Management
• Following de-energization, and when it is safe to do so, Electric Field Operations
will report impacts to infrastructure and assets from vegetation, as appropriate.
• Vegetation Management will work toward removing risk trees created by the wind
or storm event in order to re-energize system.
• Ensure contractors and field personnel are appropriately trained to perform all
relevant responsibilities under this PSPS Plan.
• Use reasonable efforts to ensure contract resources are available and prepared for
PSPS events.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Products and Services
• Provide necessary updates to outage map vendor.
• Assist with Estimated Restoration Time calculations with the Operations Managers
• Update Internal Communications Portal with current Estimated Restoration Times
(ERTs) during an event.
21

• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Geographic Information Systems
• Work with Electric Operations and Corporate Communications to ensure PSPS
boundary information for PSPS GIS maps is accurate and up to date for
emergency planning partners.
• Before wildfire season and during preliminary notifications of a potential PSPS
event, provide relevant GIS data within the confines of applicable law to public
safety partners.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Executive Officers
• Provide guidance and direction as part of the Wildfire Executive Committee where
appropriate in order to evaluate whether to initiate PSPS event.
• Provide oversight for additional Plan changes prior to next wildfire season.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Legal
• Provide legal guidance in evaluating a potential PSPS event.
• May direct AARs after a PSPS event (or potential event in which the PSPS
Assessment Team is activated).
• Involved in reviewing communications and holding statements to customers,
media, public safety partners, critical facilities, and involved communities.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
Regulatory
• May provide regulatory guidance in evaluating a potential PSPS event.
• May be involved in reviewing communications to customers, public safety partners
and critical facilities.
• Assist in/direct regulatory reporting/filing activities.
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
22

Emergency Management
• Coordination and assistance with activation and operation of EOP event.
• Help facilitate the AARs and ensure modifications to PSPS protocols are
implemented as necessary.
Finance
• Provide financial accounting assistance for EOP event (for example, providing a
Project and Task code for event tracking purposes).
• Participate in AARs and ensure modifications to PSPS protocols are implemented
as necessary.
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8. COMMUNITY OUTREACH & PREPAREDNESS
8.1. Outreach and Communication Overview
The communication and outreach leading up to, during, and after a PSPS event is critical for
all of Avista's stakeholders, which includes customers, emergency management agencies,
tribal agencies, as well as others. The communication and support provided to each of the
stakeholder groups are described below. On an annual basis, Avista will evaluate the
effectiveness of these tools and programs used to support customers and determine if
changes are needed.
8.2. Proactive Customer Communications
Although the size of Avista's service area, geographic and environmental diversity, and
unpredictable nature of weather make it challenging, Avista aims to provide as much advance
notice as reasonably possible in preparation for a PSPS event. Figure 7 provides Avista's
optimal communication timeline for PSPS events, circumstances permitting.
PSPS Timeline Description of Planned Communications
Awareness/
Pre-Wildfire Season—Provide education throughout service territory to
customers, Public Safety and Tribal Partners, monitor weather conditions
Preparedness H
and seasonal forecasts and provide internal PSPS training.
7-2 days—Monitor the weather forecasts, Internal EOP Activation, begin
PSPS notifying public safety partners of potential PSPS, begin planning for CRC
Watch operation. First notifications to affected public safety and tribal partners
and affected customers occur during this initial phase.
I PSPS 48 hours- 1 hour—Additional notification to affected public safety and
tribal partners to inform of potential pending PSPS event, additional
Warning notifications to customers within potential PSPS boundary.
MMMMIN
PS PS Execute PSPS initiation—Notify Public Safety Partners,operators of critical facilities
14 (if possible)and all customers within the PSPS boundary. Provide updates in
(Power Off) 24-hour intervals until re-energization begins.
Restoration—When re-energization begins,if possible,notification to
Restore4 affected Public Safety and Tribal Partners, operators of critical facilities and
all affected customers. Once re-energization is complete, provide final
notifications to all affected and Public Safety Partners.
Figure 7
Communication Timeline
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8.3. Coordination with Public Safety Partners, Municipalities and Tibal Entities
Strong partnerships have been developed with other utilities as well as local public safety,
emergency management agencies, and tribal entities over the last several years to assist in
the coordination for any event which impacts the communities we serve. Avista will serve as
the initiating agency in the event of a PSPS and will coordinate with the local agencies as
appropriate. Avista will collaborate with those agencies with expertise and consider any
recommendations offered by state and local emergency management agencies. Any non-
outage related issues or incidents that arise during a PSPS will be handled by local emergency
management and public safety.
Avista Regional Business Managers will maintain regular outreach with local jurisdictions to
include voice and email notifications and communication during the event. Additionally, if
requested, an Avista employee may be dispatched to the affected State or County Emergency
Operations Centers in the role of Liaison Officer and will provide a constant and direct conduit
for information.
8.4. Community Support
In addition to proactive communications to customers, and outreach to public safety partners,
municipalities, and tribal entities, there is also additional support provided to the communities
through outage maps, our CARES Team, and Community Resource Centers.
Outage Map
Effective communications regarding location of PSPS events and restoration times are
important to support customers before and during the event. Avista has an Outage Map tool
which will provide PSPS specific information regarding the location of the event, and any other
pertinent event information. The map will be updated throughout the event to keep customers
informed.
CARES Team
Avista has a Customer Service CARES Team which is engaged with medically vulnerable
customers and acts as a liaison to support those customers. A PSPS event will have a greater
impact on medically vulnerable customers necessitating additional outreach to ensure these
customers have a plan needed to be prepared for the de-energization. The CARES Team will
provide additional notifications to these customers who are medically vulnerable who rely on
24-hour electricity for medical devices.
Community Resource Centers (CRCs)
In the event of a PSPS, Avista may stand up community resource centers (CRCs) in areas
impacted by a PSPS, to be managed by Avista and staffed by Avista Community Response
Ambassadors, who are individuals volunteering to help our customers in emergency situations.
The services offered at a CRC include electronic and/or medical device charging, internet
25

access, water, light snacks, and updated real-time information to offset some of the impacts
associated with a PSPS event. The CRCs are carefully chosen to be accessible to areas most
likely to experience a PSPS.
As we continue to refine the CRC program, fine-tuning locations, resources needed, and
Avista staff training. As of year-end, 2025, seventeen Community Resource Centers (CRC)
have been identified.
In 2025, the CRC program actively installed to date its first manual transfer switch (MTS),
which allows switching portions of the designated CRC location within the building over to a
generator if the power is out, allowing the center and community to become more resilient.
The team plans to have an MTS installed at every CRC location that currently has no back-up
generation by the end of 2026.
In 2026, Avista will continue its outreach and education efforts by collaborating with multiple
partnering agencies highlighting both the importance of PSPS and the available resources the
CRC program provides for the communities we serve.
9. CONTINUOUS IMPROVEMENT
Avista will strive to continuously improve the effectiveness of this PSPS Plan, which will an
annual review and assessment. Avista participates in industry events, table-top exercises, and
other functional activities to keep abreast of industry-best practices and lessons learned so
that it may adapt its planning and processes as appropriate.
Avista's PSPS Plan is reviewed annually to ensure that it reflects Avista's current policies and
implementation procedures with updates, as needed, to the program's organizational structure,
training and education, responsibilities, operations, reporting, record keeping, and any other
changes. The end products of these reviews are new or revised documents, if necessary,
including revised versions of this Plan.
10. FINANCIAL ADMINISTRATION
Avista will track expenses related to PSPS events for WUTC and IPUC reporting and
potential recovery. Expense should be tracked for the entire PSPS event (PSPS Watch
through conclusion of the Post-Incident Review and filing the PSPS event report with the
WUTC or IPUC) to include, without limitation, time reporting, equipment and supplies
used to set up customer resource centers and provided to customers (e.g., water, ice,
etc.).
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11 . REPORTING
Employees are required to manage information regarding PSPS events pursuant to Avista's
Information Retention Policy and underlying standards. Avista will submit reports to the
WUTC and IPUC as required.
12. AFTER-ACTION REPORT
An AAR is a structured review or de-brief process used to evaluate the effectiveness of the
Plan and potential areas for improvement. This process may be performed after a PSPS event
and may be confidential at the direction of Legal to improve the PSPS processes and
procedures.
Generally, the After-Action Report could include:
• Explanation of the decision to de-energize, factors contributing to the decision.
• Explanation of how the utility determined that the benefit of de-energization
outweighed potential public safety risks.
• Location, time, and duration of event.
• Number of affected customers, broken down by residential, medically vulnerable,
commercial/industrial, and others.
• Describe wind-related damage to utility overhead powerline facilities in the areas
where power was shutoff.
• Describe customer communications and notifications.
• Whether CRCs were activated, and the location, resources provided and duration of
the CRCs.
• Describe the engagement with local and state public safety partners and community
partners with regards to advanced outreach/notification during the PSPS event.
• Summarize the number and nature of complaints received as a result of PSPS event
and include claims that are filed against Avista because of the PSPS.
• Lessons learned by Avista from the PSPS event.
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13. TRAINING
Avista will strive to provide regular training, prior to or shortly after the beginning of wildfire
season (annually), to relevant employees in executing this PSPS Plan.
14. EXERCISES
Avista's Director of Wildfire Resiliency in partnership with the Emergency Management Team
will exercise this PSPS Plan at least annually using various scenarios and testing of all or any
portion(s) of the Plan which may include:
• Improving communication efforts with public safety partners which may include
testing text and/or phone alerts
• Testing tactical operational plans such as reporting field observations or positioning
employees at manually operated disconnects to test timing for de-energization and
field inspections of distribution infrastructure
• Discussing and/or practicing roles and responsibilities of both strategic and tactical
operations, including decision-making handoffs and hypothetical scenarios
• Discussing and/or developing re-energization plans
• Testing capacity limits on incoming and outgoing communications systems
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Appendix A: Notification Plan
Avista PSPS Notification Plan
Overview
Avista's comprehensive Wildfire Resiliency Plan, launched in 2020, identified four categories of focus:
grid hardening, enhanced vegetation management, situational awareness, and emergency response
and operations. The goals of the plan have remained consistent:
1. Emergency Preparedness —To recognize wildfire as a recurring threat to infrastructure,
communities, and utility customers.
2. Protect Life and Property —To protect physical assets, property, and human lives against the threat
of wildfires. To recognize fire potential as a manageable risk element of our operating and maintenance
strategies.
3. Financial —To mitigate the probability and consequence of direct financial costs and liability
associated with large-scale fire events.
In emergency response and operations, Avista has evolved its strategies over time. Fire Safety Mode
now has an extreme setting. Customers on impacted circuits are notified when their protection settings
are increased to prepare them for potential outages.
Public Safety Power Shutoffs (PSPS), a temporary, preemptive power shut off to electrical circuits in
select areas of our system to keep communities and customers safe, is a new tactic in the plan. Due to
the potential hardships that a temporary power shut off may cause, especially to vulnerable individuals
and communities, it is critical that that in times of extremely high fire risk, Avista provides advanced
notice of a possible power shut off. This advanced notice is important to individuals and communities in
their own planning in preparation for, and living with, an electrical outage event.
Objectives
To ensure all customers are aware of any potential or planned PSPS event, the objectives of the
notification plan are to:
• Develop strategies to ensure timely notifications are made.
• Create clear and consistent messaging based on each event.
• Utilize a broad range of channels, both owned and earned, to communicate.
• Provide updated information when appropriate.
Public Safetv Power Shutoffs-Preparation
Before wildfire season begins, we work to educate customers about PSPS and what it means for them
and their communities. Corporate Communications implements a campaign to bring awareness to all
wildfire resiliency efforts and outage preparedness. We also work in coordination with community
outreach efforts to support their initiatives and strategies. The community outreach work is separate
from this notification plan, which is more tactical in implementing a PSPS.
Additionally, Corporate Communications creates messaging for every point along the PSPS timeline
and gets that messaging pre-approved before heading into Fire Safety Mode. That messaging is then
distributed to customer service and community outreach. Only the specifics like date, time and place
will need to be updated during an event. Corporate Communications also creates social media graphics
for each step and those messages are translated into Spanish, Russian, Ukrainian, Marshallese and
Mandarin so community partners can share with those they serve during a PSPS event.
29

During a PSPS Event
When a PSPS event is being considered, the following strategies and actions will be
implemented:
• Communications and Customer Service will be integrated into the Pre-EOP/EOP structure to
receive the most up-to-date information and thoroughly understand the potential impact to
customers.
• Communications and Customer Service will update pre-approved messages based on the
situation.
• For 2025, Distribution Operations will pull the list of customers on impacted circuits and share
with all departments that need the information, such as communications, customer service and
community outreach.
• Communications will determine executive availability and identify media spokespeople at the
executive and management levels.
o Determine appropriate spokespeople for different events like press conferences, media
updates, one-on-one interviews, if needed.
• Communications will develop key talking points for the specific event, including facts, status and
steps Avista is taking.
• Communications will consult with Legal and executive leadership to approve any additional
messaging.
• Communications will determine most effective media channels.
• Communications will monitor ongoing media and social media coverage and respond
appropriately.
• Communications will report out on ongoing communications efforts at all EOP meetings.
• Communications will update messaging as event develops and give updates to customers at a
minimum of every 24 hours after PSPS has been implemented.
Notification Methods Available:
• Customer email
• Customer IVR callout and global message, initiated by Customer Service with messaging from
Corp Comm
• Press release to local media
• Website banner and wildfire/PSPS page updates
• Avista social media channels (i.e. Facebook, X)
• Outage map updated
• Outage text messages sent to customers — method TBD
• Messages amplified by regional partners and community-based organizations
30

Timeline During Event:
Watch Warning Imminent Happening Response Restoration
When: 1 48-24 24-4 hours 4-1 hours During As soon as it's PSPS is over
hours safe
What: PSPS is PSPS looks Power is being Power is Customers will Restoration is
possible necessary shut off shut off see crews complete
respond n
How*: e Email * Email * Email * Email * Email * Email
• Outage • Outage • Outage • Outage • Outage • Outage
map map map map map map
• Social * Social * Social * Web • Social * Social
media media media banner media media
• IVR • IVR/global and * IVR/global * IVR
* Web message webpage message * Web
banner and * Web updates * Web banner
webpage banner and * Text banner and and
updates webpage * Press webpage webpage
• Text updates release updates updates
* Press • Text • Text * Text
release • Press * Press
release release
Who: Broad Impacted Impacted Impacted Impacted Impacted
customer customer list customer list customer list customer list customers and
list and broad comms
community
partners
*Possible channels that may be used depending on situation and timing.
;v M
PSPS Watch PSPS Warning PSPS Imminent PSPS Outage Alert PSPS Updates PSPS Over
Sent when Sent when Sent when Sent when Sent as needed and Sent when
a PSPS event a PSPS event a PSPS event a PSPS when restoration power has
is possible. is likely. is imminent. outage begins. work begins. been restored.
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Coordination with Stakeholders:
Notifications to audiences outside of broad customer communications are conducted by the following
roles/teams within Avista:
• Wildfire Team
o Fire Agencies
o Emergency Medical Response Agencies
o DNR/IDL
• Regulatory Officer
o WUTC and/or IPUC
• Tribal Relations Advisor
o Any impacted Tribal partners
• Regional Business Manager (RBM) Team
o Local elected/community leaders
o Red Cross
o Community-based organizations
• Account Executive (AE) Team
o Critical infrastructure
o Commercial customers
• Customer Assistance Referral and Evaluation Services (CARES) Team
o Medically vulnerable customers
• Corporate Communications Team
o Avista employees
Notification Cancellation
If conditions change and fire risk has decreased, customers will be informed that Avista will not
implement a PSPS event. All relevant communication channels will reflect that new message. If an
elevated protection setting is still warranted, customers will be notified of that, as they may still be more
likely to experience an outage.
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