LRA Legislation Factsheet - Flipbook combined - Flipbook - Page 9
FHSZ Frequently Asked Questions
SRA Questions
Why is my property in a different zone than the adjacent area, which looks similar?
In wildland areas, zone edges are a result of the way zones are delineated. Specifically, zones
represent areas of similar slope and fuel poten琀椀al. Zone boundaries divide zones based on
geographic and vegeta琀椀on features that align with fire hazard poten琀椀al; although, at a local scale,
it may appear that the immediate area is similar on both sides of the edge. The class value within a
zone is based on the average hazard score across the whole zone, so areas that are in the same
zone but not immediately adjacent to a local area can have an influence on the final zone
classifica琀椀on.
What is the difference between the various Fire Hazard Severity Zones?
Classifica琀椀on 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 func琀椀on of modeled flame length under the worst condi琀椀ons and annual
burn probability. Both these factors generally increase with increasing hazard level, but there may
be instances where one value is Very High and the other is low, pushing the overall hazard into a
more intermediate ranking. On average, both modeled flame length and burn probability increase
by roughly 40-60% between hazard classes.
Is the GIS data for Fire Hazard Severity Zones available for download?
The data inputs used to develop the Fire Hazard Severity Zones are iden琀椀fied in the Ini琀椀al
Statement of Reasons (ISOR) Title 19 Development (ca.gov). CAL FIRE has developed an addi琀椀onal
data package which consists of sequen琀椀al modeling steps, including any data inputs that were not
already publicly available and referenced in the ISOR. The data package encompasses 34 spa琀椀al
datasets and 8 tables, provided in raster, polygon, and table format. These datasets are forma琀琀ed
for Esri ArcGIS so昀琀ware, except for four tables provided in Excel. Ten of the datasets are updated
versions used to produce an edited SRA FHSZ map following the public comment period that
ended April 4, 2023. Upon formal adop琀椀on of the FHSZ map, the final SRA FHSZ geospa琀椀al data
file will become available. The data package is available on the FHSZ website Fire Hazard Severity
Zones (ca.gov) under the science and methods banner.
