Cal Fire rolls out new fire hazard maps for Central California. Up next: L.A.

The California Department of Forestry and Fire Protection released new fire-hazard severity maps Monday that added thousands of acres within the purview of local fire departments across agricultural Central Valley counties that previously had zero acres zoned as such. The Central Coast’s Monterey and San Luis Obispo counties saw their fire-hazard acreages increase more than four- and fivefold, respectively.

In total, the agency added over 1.2 million acres into the zones, over 300,000 of which are in severity zones where many of the state’s fire safety regulations apply.

The maps, covering 15 counties in Central California, are part of Cal Fire’s two-month rollout of new hazard zones for the regions where local city and county fire departments are responsible for responding to blazes.

The rollout marks the first update in over a decade to Cal Fire’s hazard zones in local fire department responsibility areas — which are referenced in at least 50 different sections of California’s codes, from street and highway codes to healthy and safety codes to building codes. Previously, the agency only mapped “very high” severity zones for the local responsibility areas. The new maps add what the agency now defines as “high” and “moderate” severity zones as well.

The state Legislature first ordered Cal Fire to update its maps and include the new “high” and “moderate” zones in 2021. In the same law, the Legislature also extended many of the fire-safety regulations that applied to the “very high” zone into the new “high” zone as well. These regulations include stricter building codes for new construction, which require homeowners to use fire-resistant building material, install multi-pane windows that are less likely to shatter in a fire and cover open vents that embers could easily enter the home through.

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In September 2023, Cal Fire updated its maps for all three levels of hazard zones for areas where the state is responsible for responding to fires. The maps published Monday apply also to areas where local agencies are responsible.

Cal Fire is releasing these maps in sections; this is the third of four planned, with only Southern California left. So far, inland Northern California and Central California saw roughly fivefold increases in acreage in these zones for local responsibility areas. Coastal Northern California saw a sixfold increase. The agency will release the Southern California maps on March 24.

In these most recently published maps, Monterey and San Luis Obispo counties saw significant increases, with the cities that share their name as no exceptions. The city of Monterey saw a doubling in acreage from just over 1,100 acres to over 2,200 acres for the highest two zones, while the city of San Luis Obispo saw its acreage increase from just around 750 acres to over 3,400.

Santa Barbara and Ventura counties to the south saw more modest percentage increases, but notably, Ventura’s Simi Valley and Thousand Oaks saw their zones increase by more than 2,000 acres each. (Meanwhile, the city of Santa Barbara was the only one of the 93 cities mapped to see a decrease in acreage.)

Cal Fire’s zones represent the fire hazard areas face: a combination of the chance of a fire reaching the area and its potential intensity — not the risk of specific properties sustaining damage in a wildfire.

To calculate the zones, Cal Fire uses vegetation and climate data to compute the probability that wildlands will burn and with what intensity. For developed land, the agency looks at the hazard of the surrounding areas and estimates how far fire could spill over into urban regions.

Cal Fire treats agricultural areas — which make up much of the Central Valley — similarly to urban areas.

“The non-wildland zoning doesn’t involve any direct sort of mechanistic fire behavior assessment,” David Sapsis, a Cal Fire research manager who oversees the mapping efforts, told The Times in January before the rollout began.

“It basically says you’ve got a wildland piece and an urban area or agricultural area next to it,” he said. The urban and agricultural area adjacent to the wildland “gets the same wildland score … and then it will decay with distance away.”

Many Central Valley counties with significant agricultural land that previously had zero acres zoned in the local fire departments’ responsibility areas now have thousands. Much of those are in the new “high” zone — including in Fresno, Madera, Tulare and Kern counties with their almond, pistachio and citrus orchards.

Cal Fire would not comment on why specific regions saw an increase or decrease in the “very high” zone. The agency did say that recent land development could produce changes in hazard zoning, and noted that the new maps use updated and more detailed climate and weather data, as well as a new method for estimating how far embers can bring fire into developed areas.

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However, according to Cal Fire, the models do not account for changes in vegetation due to recent wildfires, nor the home hardening and brush management communities have undertaken.

The release triggers a roughly five-month clock in which local governments must accept public input on the new maps, officially adopt them and begin applying the heightened regulations. Local jurisdictions can choose to increase the severity zoning of regions, but they cannot decrease them.

Cal Fire is adamant the hazard maps have no direct effect on residents’ insurance rates, saying they model hazard — the chance of an area experiencing wildfire — not the risk of specific homes burning down.