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The California Department of Forestry and Fire Protection began rolling out a long-awaited update to its fire hazard severity zones Monday, which is set to more than double the number of acres in local fire jurisdictions that must comply with stricter fire safety building codes.
Previously, the state mapped and applied fire safety regulations only to local areas with the highest possible fire hazards, deemed “very high.” But in 2021, the state Legislature ordered Cal Fire to expand the mapping to include “high” hazard zones so the Legislature could apply fire-safety building regulations to the new “high” zones as well.
The new maps are expected to expand the roughly 800,000 acres currently in local fire jurisdictions zoned as “very high” by an additional 247,000 acres. Some 1.16 million acres will be categorized into the new “high” zones, according to a press release from the governor’s office.
Cal Fire will also release new “moderate” hazard zones, its lowest hazard classification that is rarely referenced in fire safety regulations, but did not state how many acres it would encompass.
The agency hasn’t released maps for these local areas — on city and county land where local fire departments, not Cal Fire, are responsible for responding to fires — since 2011.
Cal Fire initially planned to release the maps in January, but the Los Angeles firestorms halted the rollout. Cal Fire officials said many of the agency’s mapping personnel, including scientists, were supporting the firefighting and recovery efforts and that they didn’t want to burden communities already facing the daunting task of rebuilding.
However, after Gov. Gavin Newsom signed an executive order Thursday on fire safety that, in part, ordered Cal Fire to release the maps, the agency obliged.
The agency began the rollout by sending the new maps to local fire jurisdictions across inland Northern California on Monday. Cal Fire will send maps for coastal Northern California jurisdictions on Feb. 24, the Central Coast and Central Valley on March 10 and Southern California — including L.A., San Bernardino and San Diego counties — on March 24.
Once each of the hundreds of cities and counties across the state receives the maps, they have 30 days to make the new zones public and 120 days to officially adopt the maps and begin applying the heightened fire-safety regulations.
The local jurisdictions can opt to increase the hazard area or ratings — but cannot decrease them.
The severity zones are referenced in at least 50 different pieces of legislation, codes, grants and other state rules and documents.
Many regulations apply only to new constructions and significant repairs or remodels: They include Chapter 7A building codes that require property owners building in the “very high” and now “high” zones to take home-hardening measures, including using ignition-resistant materials, covering vents that could allow embers to enter homes and cause ignition from the inside out and installing multipaned or fire-resistant windows.
In 2021, the state passed a law requiring local jurisdictions to consider fire hazard for community-land-use planning, not just individual structures, in “very high” hazard zones. For example, governments must now take into account evacuation routes and the peak stress on the water supply that could occur during disasters, and they must locate essential public facilities like hospitals and emergency command centers outside of high fire-risk areas “when feasible.”
Cal Fire is adamant that its maps will not impact Californians’ fire insurance rates. Insurance companies typically have their own risk-evaluation models, and are therefore unlikely to raise or lower rates based on how Cal Fire grades a given area’s fire hazard.
That said, Cal Fire’s assessment could lead to changes in regulation that require property owners to harden their homes and maintain defensible spaces around them. And, in theory, that could actually lead to decreased insurance rates — especially if communities as a whole all take such protective measures.
For example, communities designated as “firewise” by the National Fire Protection Association — including Topanga, which sits squarely in a “very high” hazard zone — can get insurance discounts from several providers.
Cal Fire has historically updated its fire hazard maps only when the state Legislature requested it. After the 1980 Panorama fire in San Bernardino County that killed four, the state first ordered the agency to create the maps for the wildland regions where it was responsible for responding to fires. Then, following San Diego County’s 2003 Cedar fire that killed 15 and destroyed over 2,800 structures, the Legislature ordered Cal Fire to expand the maps to the more developed areas where local fire departments are responsible for managing fires. And in the aftermath of California’s devastating 2020 fire year, the state Legislature asked Cal Fire to complete its most recent round of updates, including the new “high” and “moderate” zones for local fire jurisdictions.
Cal Fire said the mapping process can take years since it must scrutinize detailed data for the entire state to model fire hazard and coordinate with hundreds of individual cities and counties.
Meanwhile, the Legislature sent mixed signals about its opinion on the Cal Fire models; in 2024 it considered killing the hazard zones altogether and replacing them with “wildfire mitigation areas.” Proponents argued it would streamline regulations; however, its opponents — who called it a thinly veiled attempt to build more housing in fire-prone areas — won out.
Cal Fire told fire safety advocates that it now plans to update the maps roughly every five years.
This first stage of a rollout comes shortly after Cal Fire acknowledged weaknesses in its model approach that resulted in the agency zoning only 21% of the Altadena properties within the perimeter of the Eaton fire as “very high” fire hazard, according to an analysis by The Times. The independent fire risk modeling company First Street had previously identified 94% as having “severe” or “extreme” wildfire risk.
The discrepancy between Cal Fire’s and First Street’s maps is mostly due to how the two have historically considered the threat of wildfires in more developed parts of the state.
The vast majority of homes destroyed in the Eaton fire were outside of Cal Fire’s “very high” fire hazard severity zones, yet a newer approach by an independent company had found Altadena had “severe” wildfire risk.
For wildlands, Cal Fire determines hazard zones by looking at vegetation data, topology and weather and climate patterns to calculate the probability of wildfire occurring and its potential intensity. For populated areas, Cal Fire looks at the hazard of surrounding wildlands and estimates how far a fire could travel into the developed regions.
However, the agency’s models are a snapshot. They do not simulate how fire spreads, nor do they simulate how houses could fuel a fire.
First Street uses a newer approach that considers both wildlands and developed areas as fuel and simulates millions of virtual fires to watch how they spread through time.
Cal Fire said its new maps would largely leave these weaknesses unaddressed, given that First Street’s nascent approach currently lacks the decades of scientific support their current approach has.
However, the agency did make slight adjustments to its model that resulted in an increase of acres zoned as “very high,” including the use of more detailed climate and extreme-weather data.
