New fire maps increase hazard zones in L.A. and SoCal by 3.5 million acres

The California Department of Forestry and Fire Protection released updated fire-hazard severity-zone maps for Los Angeles County for the first time in over a decade on Monday, adding more than 440,000 acres to the county’s hazard zones, including a 30% increase in acres zoned in the highest severity rating.

The release — which includes all of Southern California and marks the end of the agency’s two-month, statewide rollout — sets off a roughly five-month clock for L.A. city and county to receive public input, make adjustments, and begin enforcing heightened fire-safety regulations within the new zones.

The new Cal Fire maps are only for areas where local fire departments, like the Los Angeles Fire Department and Los Angeles County Fire Department, are responsible for responding to blazes. Previously, Cal Fire only mapped the highest severity rating, “very high,” for these local responsibility areas. The new maps include Cal Fire’s “moderate” and “high” zones as well.

Cal Fire most recently updated all three zones for the areas where the state responds to fires in September 2023. However, the last time the agency updated its maps for areas where local fire departments are responsible was in 2011.

The city of L.A. saw its acreage in the “very high” zone increase by 7%. The addition of the new “moderate” and “high” zones led to the total acreage in the fire severity hazard zones increasing by 24%.

The unincorporated areas in L.A. County that rely on LACFD, however, saw their acreage in the “very high” zone more than triple. Much of the unincorporated areas — which make up over 65% of the county and include Altadena, the outskirts of Santa Clarita and Palmdale areas and Puente Hills near Whittier — are wildlands or exist at the wildland-urban interface, which are more prone to fire.

“Today’s release of updated hazard assessment maps from Cal Fire … underlines the ongoing wildfire crisis that California is experiencing,” Rep. George Whitesides (D-Agua Dulce) said in a statement. “We must act fast and at scale to protect our communities and make sure insurance markets work for everyone.”

With the rollout complete, California as a whole now has more “very high” hazard zone acres than ever before. Cal Fire mapped a grand total of 6.8 million acres into the local responsibility area hazard zones: “very high” zones grew 35%, from 860,000 acres to nearly 1.2 million; meanwhile, 1.2 million and 4.5 million acres were placed into the new “high” and “moderate” zones, respectively.

The hazard severity zone maps are referenced in more than 50 sections of California law. They require homeowners in “high” and “very high” hazard zones to follow fire-safe building codes for new construction — including installing multi-pane windows that are less likely to break in extreme heat and covering vents and other openings to prevent embers from entering the house. Homeowners in the “very high” zones must maintain defensible space around their properties and disclose the “very high” status when they put their houses up for sale

The legislature has also required local governments in heightened severity zones to routinely review evacuation routes and account for the potential peak stress on water supplies during a disaster. Local governments must also locate essential public facilities like hospitals and emergency command centers outside of heightened fire hazard zones “when feasible,” according to the law.

Cal Fire originally planned to release the maps in mid-January; however the L.A. firestorms that month forced the agency to delay as it moved significant scientific resources to supporting the firefight and relief efforts.

In the new maps, the Pacific Palisades and Malibu remain blanketed under a red “very high” zone, just as they did in Cal Fire’s old maps from 2011. Altadena, on the other hand, remains largely unzoned, indicating a hazard lower than “moderate,” just as it did in the old maps.

An analysis by The Times found that only 21% of the properties within the Eaton fire’s perimeter were designated as having “very high” fire hazard. Yet, an independent assessment by the public-benefit company First Street had identified 94% as having “severe” or “extreme” wildfire risk, meaning they had at least a 1 in 7 chance of experiencing wildfire in a 30-year window.

Cal Fire research manager David Sapsis, who oversees the agency’s mapping efforts, acknowledged that the models Cal Fire uses to create its maps cannot fully predict the dynamic spread of wildfire into urban areas. Cal Fire’s model instead accounts for the vegetation type, topology, climate and weather for wildland areas to calculate the probability of an area burning and the likely intensity of the blaze. From this, it calculates how far a blaze would likely spill over into urban areas.

The team also intentionally chose to leave out what it calls “outlier” events like the 2017 Tubbs fire, because, they said, it would have led to overly conservative zoning. Another outlier event: the Eaton fire, which, like the Tubbs fire, was driven by relentless, powerful winds that drove the blaze deep into a populated area.

First Street approaches it somewhat differently. The company creates a virtual representation of California that includes both vegetation and human infrastructure of the state’s urban areas, and simulates how fires would likely spread, including into areas like Altadena. If Cal Fire’s model is a snapshot of how fire acts, First Street’s is a motion picture.

Sapsis acknowledged he’d like to use newer approaches like First Street’s in the future. For its 2025 maps, Cal Fire made only slight modifications to its model, including the use of more up-to-date climate and extreme weather data. It also used a new model for estimating how far embers can bring fire into developed areas.

Other changes in the real world — such as new housing developments that changed an area’s classification from wildland to urban — also resulted in modifications to the Cal Fire maps.

In the latest release — comprising all of Southern California, including San Diego, San Bernardino, Riverside and Orange counties — the cities of Hesperia and Jurupa Valley saw the most significant percentage increase in acres zoned, with the cities’ total averages in hazard zones increasing more than 35- and 45-fold, respectively. Jurupa Valley saw its “very high” zone expand from 226 acres to 6,195. Hesperia’s grew from 715 to 15,359.

The cities of Chino Hills, Lancaster and Santa Clarita saw significant increases in their “very high” zones; in all three cities, the zones grew by more than 13,000 acres.

The number of acres zoned as “very high” in San Diego decreased by nearly 30%; however, its total acreage in hazard zones still slightly increased thanks to the new “moderate” and “high” zones.

Only a handful of cities across the state saw decreases in the total acreage zoned, including Rancho Palos Verdes in L.A. County and Oakland in the Bay Area.

“I’ll be quite honest with you, before these maps were produced, I thought the very high fire severity zones were really going to reach deep deep down into Altadena, and they haven’t,” said LACFD Deputy Fire Chief Albert Yanagisawa. “I asked Cal Fire, seeing as what happened, is there a reason the maps were not changed, and what they said was, specifically, their model is for wildland fire modeling. It’s not utilized and it shouldn’t be utilized for [urban] conflagration modeling.”

Cal Fire has so far declined to comment on what drove changes in specific counties and cities.

Now, local jurisdictions have 120 days to accept public input on the maps and work with Cal Fire to issue an official ordinance implementing them. Typically, ordinances take effect about 30 days after they’re issued. At that point, the heightened fire safety regulations would apply to the new zones.

Local jurisdictions like L.A. city and county are allowed to increase the severity of a zone and add additional acres to a zone; however, they cannot decrease the severity of zones or remove acres from them.

These maps are a “critical tool for identifying high fire hazard areas and strengthening fire safety policies across our communities,” said County Supervisor Kathryn Barger. “For those working to rebuild after the Eaton fire, I want to emphasize that these maps provide essential information to guide your rebuilding efforts. They reflect the latest fire hazard assessments and will help ensure our homes and infrastructure are rebuilt with safety and resilience in mind.”

Fire safety advocates have attributed the continuing upward trend of acre zones to a litany of factors from development in fire-prone areas, ecosystem changes and climate change.

“Yes, climate change has obviously and absolutely impacted the severity of our wildfires and where they are happening, but way before there were climate impacts, there were land-use decisions,” said Howard Penn, executive director of the Planning and Conservation League, a California-based nonprofit. “We have been sprawling into the wildlands for the last 75-plus years with very little consideration of the impacts.”

This is a developing story.