HomeMy WebLinkAboutStaff Report 2504-4596CITY OF PALO ALTO
CITY COUNCIL
Monday, June 09, 2025
Council Chambers & Hybrid
5:30 PM
Agenda Item
14.FIRST READING: Adoption of an Ordinance amending Section 15.04.410 (Definition of
Wildland-Urban Interface Fire Area) to adopt and incorporate the 2025 CAL FIRE Fire
Hazard Severity Zone (FHSZ) Map for the City of Palo Alto. CEQA status: Not a Project.
City Council
Staff Report
From: City Manager
Report Type: CONSENT CALENDAR
Lead Department: Fire
Meeting Date: June 9, 2025
Report #:2504-4596
TITLE
FIRST READING: Adoption of an Ordinance amending Section 15.04.410 (Definition of Wildland-
Urban Interface Fire Area) to adopt and incorporate the 2025 CAL FIRE Fire Hazard Severity
Zone (FHSZ) Map for the City of Palo Alto. CEQA status: Not a Project.
RECOMMENDATION
Staff recommends that the City Council adopt Exhibit the CAL FIRE Fire Hazard Severity Zone
(FHSZ) map, as recommended by the California Department of Forestry and Fire Protection (CAL
FIRE), for areas within the City of Palo Alto's jurisdiction.
EXECUTIVE SUMMARY
CAL FIRE is mandated by state law to identify and map areas with significant fire hazards, and
periodically revise and update its designation of zones. These maps, known as Fire Hazard
Severity Zone (FHSZ) maps, categorize areas based on factors that influence fire likelihood and
behavior. Updates in state law since 2021 now require that a local agency, including the City of
Palo Alto, designate by ordinance the moderate, high, and very high FHSZs in its jurisdiction
within 120 days of receiving recommendations from the State Fire Marshal. (Gov. Code
51179(a)).
Recent updates to the state’s FHSZ maps were issued for the Bay Area, including Palo Alto,
February 24, 2025.The City has provided opportunities for public review and comment on the
CAL FIRE FHSZ map March 26 through April 30, 2025, and adoption of the CAL FIRE FHSZ map is
a necessary next step to protect the City of Palo Alto from the increasing threat of wildfires. It
ensures compliance with state law, enhances public safety, and promotes responsible land-use
planning. Staff recommends that the City Council adopt the map as presented. Under state law,
a local agency has discretion to add areas not identified by the State Fire Marshal or increase
the fire hazard severity identified by the state, but not to remove areas or reduce the hazard
severity level (Gov. Code 51179(b)).
BACKGROUND
•Wildfire Preparedness: They provide critical information for residents, property owners,
and the City to understand the level of fire hazard in specific areas.
•Building Codes: The maps inform building code requirements, particularly for new
construction and renovations, to enhance structural resistance to wildfire.
•Defensible Space: The maps guide the implementation and enforcement of defensible
space regulations, which are crucial for protecting structures from approaching
wildfires.
•Emergency Planning: The maps assist in developing effective wildfire mitigation and
response plans.
•Designating areas where California’s defensible space standards and wildland urban
interface building codes are required.
•General plan considerations: Local governments may consider them in their general
plans.
1. The Policy
& Services Committee reviewed an audit completed by the City Auditor regarding wildfire
preparedness2 and an expanded report outlining activities underway, this was approved
unanimously and is scheduled for the Council Consent Calendar. In addition, the following items
1 Palo Alto Begins Wildfire Preparedness Public Discussions; https://www.paloalto.gov/News-Articles/City-
Manager/Palo-Alto-Begins-Wildfire-Preparedness-Public-Discussions
2 Policy & Services Committee,
are scheduled in June that continue the conversation around wildfire preparedness for the City
of Palo Alto:
•City Council will consider approval of an easement in the Palo Alto foothills to support
the undergrounding of the electric transmission line (upon approval by Mid-Peninsula
Open Space District).
•Utilities Advisory Commission will review the 2025 Utilities Wildfire Mitigation Plan at
their meeting on June 4.
•The City’s Foothills Fire Management Plan updates and the Santa Clara County
Community Wildfire Protection Plan, a combined effort will be finalized.
•City Council will consider annual weed abatement orders involving private properties.
ANALYSIS
•Compliance with State Law: State law mandates that local agencies adopt the FHSZ
maps.
•Enhanced Public Safety: Adopting the map enables the City to better protect its
residents and property from the increasing threat of wildfires. It provides a foundation
for implementing effective mitigation measures and enforcing necessary regulations.
•Improved Planning and Development: The map will inform land-use planning and
development decisions, ensuring that new construction and infrastructure projects are
designed to minimize fire risks.
•Access to Funding: Adoption of the FHSZ maps may be a prerequisite for accessing
certain state and federal funding for wildfire prevention and mitigation projects.
•Understanding Fire Hazard Severity Zones: It is important to note that the Fire Hazard
Severity Zone map evaluates "hazard," not "risk." "Hazard" is based on the physical
conditions that create a likelihood and expected fire behavior over a 30 to 50-year
period without considering mitigation measures. "Risk" is the potential damage a fire
can do to the area under existing conditions, accounting for modifications such as fuel
reduction projects, defensible space, and ignition-resistant construction.
Key elements of the Fire Hazard Severity Zone model: The fire hazard severity model for
wildland fire has two key elements: 1) probability of an area burning and 2) expected fire
behavior under extreme fuel and weather conditions. The zones reflect areas that have similar
burn probabilities and fire behavior characteristics.
•Factors considered in determining fire hazard within wildland areas are fire history,
flame length, terrain, local weather, and potential fuel over a 50-year period.
•Outside of wildlands, the model considers factors that might lead to buildings being
threatened, including terrain, weather, urban vegetation cover, blowing embers,
proximity to wildland, fire history, and fire hazard in nearby wildlands.
•FHSZs are not a structure loss model, as key information regarding structure ignition
(such as roof type, etc.) is not included.
•The model places an emphasis on the spread of embers. Embers can travel long
distances in the wind and ignite vegetation, roofs, attics, and decks.
•Areas immediately adjacent to wildland receive the same FHSZ score as that wildland
where fire originates, and the model then produces lower scores as the distance to the
wildland edge increases.
•In wildland areas, zone edges are a result of the way zones are delineated. Zones
represent areas of similar slope and fuel potential.
How Fire Hazard Severity Zones are determined: CAL FIRE used the best available science and
data to develop and field-test a model that served as the basis of zone assignments. The model
evaluated the probability of the area burning and potential fire behavior in the area.
•Many factors were included, such as fire history, vegetation, flame length, blowing
embers, proximity to wildland, terrain, and weather.
•A 2 km grid of climate data covering the years 2003-2018 is being used in the update.
The previous model used stock weather inputs across the state to calculate wildland fire
intensity scores. The updated model adjusts fire intensity scores based on the most
extreme fire weather at a given location, considering temperature, humidity, and wind
speed.
•Ember transport is being modeled based on local distributions of observed wind speed
and direction values instead of using a generic buffer distance for urban areas adjacent
to wildlands.
•Classification of a wildland zone as Moderate, High, or Very High fire hazard is based on
the average hazard across the area included in the zone, which have a minimum size of
200 acres.
•In wildlands, hazard is a function of modeled flame length under the worst conditions
and annual burn probability. Classification outside of wildland areas is based on the fire
hazard of the adjacent wildland and the probability of flames and embers threatening
buildings.
State Responsibility Area (SRA): SRA is the area where the state has financial responsibility for
wildland fire protection and prevention. Incorporated cities and federal ownership are not
included in SRA. CAL FIRE is responsible for fire prevention and suppression within the SRA.
Local Responsibility Area (LRA): Local Responsibility Areas (LRA) are incorporated cities, urban
regions, agricultural lands, and portions of the desert where the local government is
responsible for wildfire protection. CAL FIRE uses an extension of the state responsibility area
Fire Hazard Severity Zone model as the basis for evaluating fire hazard in Local Responsibility
Area.
•The Local Responsibility Area hazard rating reflects flame and ember intrusion from
adjacent wildlands and from flammable vegetation in the urban area.
•CAL FIRE’s Land Use Planning Program provides support to local governments by
providing fire safety expertise on the State’s wildland urban interface building codes,
wildfire safety codes, as well as helping in the development of the safety elements in
general plans.
•CAL FIRE uses the same modeling data that is used to map the State Responsibility Area
for Local Responsibility Areas.
•New legislation, Senate Bill 63 (Stern, 2021), now requires the adoption of all three Fire
Hazard Severity Zone classes in the Local Responsibility Area. Previously only Very High
Fire Hazard Severity Zones were required for adoption in Local Responsibility Areas.
FISCAL/RESOURCE IMPACT
STAKEHOLDER ENGAGEMENT
ENVIRONMENTAL REVIEW
ATTACHMENTS
APPROVED BY:
NOT YET APPROVED Attachment A
1
027051925
Ordinance No. ____
Ordinance of the Council of the City of Palo Alto Amending Section 15.04.410 (Definition of
Wildland-Urban Interface Fire Area) of the Palo Alto Municipal Code to adopt and incorporate
the 2025 Fire Hazard Severity Zone Map Issued by the State Fire Marshal
The Council of the City of Palo Alto does ORDAIN as follows:
SECTION 1. Findings and Declarations. The City Council finds and declares as follows:
A. To better prepare for wildfires, the California Department of Forestry and Fire Protection
(CAL FIRE) is required to periodically review its recommended classifications of fire hazard
severity zones throughout California. The state legislature has found that the prevention
of wildfires is a matter of statewide concern, not a municipal affair.
B. The State released updated 2025 Fire Hazard Severity Zone (FHSZ) maps, and requires all
local jurisdictions, including Palo Alto, with moderate, high, and very high fire hazard
severity zone recommendations to designate those zones by ordinance within 120 days
from receiving recommendations from the State Fire Marshal.
C. State law also requires that the City post the maps indicating CAL FIRE’s FHSZ
recommendations publicly for comment within 30 days of receipt, which the City
conducted from March 26 - April 30, 2025.
D. After consideration of public comments, the City will rely on the latest recommendations
of CAL FIRE in its published FHSZ maps, notwithstanding local discretion to impose more
restrictive fire and public safety requirements.
E. As a result of adopting the updated FHSZ map for Palo Alto, the City’s Municipal Code
definition of the wildland-urban interface in Section 15.04.410 needs to address zones
designated as moderate and high fire hazard severity, in addition to those zones
designated as very high fire hazard severity.
SECTION 2. Section 15.04.410 Section 4902.1 Definition of wildland-urban interface fire
area is hereby amended to read as follows (additions in underline format and deletions
in strikethrough format):
5.04.410 Section 4902.1 Definition of wildland-urban interface fire area.
The definition of "wildland-urban interface fire area" in Section 4902.1 is amended to read as
follows:
WILDLAND-URBAN INTERFACE FIRE AREA (WUI) A geographical area identified by the State of California as a "Fire Hazard Severity Zone" in accordance with Public Resources Code Sections 4201 through 4204 and Government Code Sections 51175 through 51189, or other areas
designated by the enforcing agency to be at a significant risk from wildfires. Within the city limits
of the City of Palo Alto, "Wildland-Urban Interface Fire Area" shall also include all areas west of
Interstate 280, and all other areas recommended as a “Moderate,” “High,” and "Very High” Fire
Hazard Severity Zone" by the Director of the California Department of Forestry. The map,
approved by the Council of the City of Palo Alto, is hereby incorporated by reference, and
entitled, “Fire Hazard Severity Zones in Local Responsibility Area - City of Palo Alto”, dated February 24, 2025 (Exhibit A).
NOT YET APPROVED Attachment A
2
027051925
SECTION 3. Effective Date. This Ordinance shall be effective on the thirty-first date
after the date of its adoption.
SECTION 4. CEQA. The City Council finds and determines that this Ordinance is not a
project within the meaning of section 15378 of the California Environmental Quality Act
(“CEQA”) Guidelines because adoption of the state FHSZ map and updating a statutory
definition involves no action with potential for resulting in physical change in the environment,
either directly or ultimately. In the event that this Ordinance is found to be a project under
CEQA, it is subject to the CEQA exemption contained in CEQA Guidelines section 15061(b)(3)
because it can be seen with certainty to have no possibility of a significant effect on the
environment in that this Ordinance simply clarifies existing local regulations.
INTRODUCED AND PASSED:
AYES:
NOES:
ABSENT:
ABSTENTIONS:
ATTEST:
__________________________ _____________________________
City Clerk Mayor
APPROVED AS TO FORM: APPROVED:
__________________________ _____________________________
City Attorney or designee City Manager
_____________________________
Fire Chief, Palo Alto Fire Department
City and County boundaries as of 10/22/24 (CA Board of Equalization)
CAL FIRE State Responsibility Areas (SRA25_1)
CAL FIRE Fire Hazard Severity Zones (FHSZSRA23_3, FHSZLRA_25_1)
Data Sources:
Daniel Berlant, State Fire Marshal, CA Department of Forestry and Fire Protection
Joe Tyler, Director/Fire Chief, CA Department of Forestry and Fire Protection
Wade Crowfoot, Secretary for Natural Resources, CA Natural Resources Agency
Gavin Newsom, Governor, State of CaliforniaThe State of California and the Department of Forestry and Fire
Protection make no representations or warranties regarding the
accuracy of data or maps. Neither the State nor the Department shall
be liable under any circumstances for any direct, special, incidental,
or consequential damages with respect to any claim by any user or
third party on account of, or arising from, the use of data or maps.
and other relevant factors including areas where winds
have been identified by the Office of the State Fire Marshal
as a major cause of wildfire spread.
statewide criteria and based on the severity of fire hazard that is
expected to prevail in those areas. Moderate, high, and very high fire
hazard severity zones shall be based on fuel loading, slope, fire weather,
Government Code section 51178 requires the State Fire
Marshal to identify areas in the state as moderate, high,
and very high fire hazard severity zones based on consistent
Waterbody
Federal Responsibility
Area (FRA)Unzoned LRA
Incorporated City
Projection: NAD 83 California Teale Albers
Scale: 1:97,000 at 11" x 17"
0 1 2 3 4 5 6 7Km
0 1 2 3 4Mi
Very High High Moderate
Fire Hazard Severity Zones in State Responsibility Area
(SRA), Effective April 1, 2024
Very High High Moderate
Fire Hazard Severity Zones (FHSZ) in Local Responsibility
Area (LRA), as Identified by the State Fire Marshal
Palo Alto
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February 24, 2025
As Identified by the
State Fire MarshalLocal Responsibility Area
Fire Hazard Severity Zones
CITY OF PALO ALTO – SANTA CLARA COUNTY
Exhibit A