Board adopts state fire hazard severity zone maps for Napa County local responsibility areas

The Napa County Board of Supervisors on May 6 voted unanimously to adopt updated fire hazard severity zone maps developed by the California Office of the State Fire Marshal for the county—s Local Responsibility Area (LRA). The maps are the first major statewide update since 2007 and require local adoption of three zone classes (moderate, high and very high). The state mandated adoption deadline requires local jurisdictions to adopt the maps within 120 days of release.

What the maps do: The State Fire Marshal—s updated maps use recent fire behavior science, vegetation and fuel‑load data, terrain and local weather patterns, and ember‑exposure modeling to identify areas likely to experience extreme fire behavior over a 50‑year horizon. Jason Downs, the county fire marshal, emphasized the maps indicate hazard (where extreme fire behavior is more likely) and do not measure structure‑level risk or present a prediction of building loss; short‑term mitigation such as recent fuel treatments or defensible‑space work are not reflected in the map.

How the maps will be applied locally: Once adopted, the maps bring county properties in newly mapped areas under rules that already apply in State Responsibility Areas (SRAs): Chapter 7A building standards (WUI construction/fire‑resistant construction standards), defensible space requirements (government code 51182), Napa County road and street standards for emergency access and water supply, and real‑estate disclosures such as AB 38 wildfire hazard reports. Downs said the change means jurisdictions and permitting staff will apply those codes in LRA locations newly mapped as high or very high.

Local process and outreach: The county said it has provided public notice and a press release and will continue outreach; the fire marshal—s office said defensible‑space inspectors have been increased to six seasonal staff this year to conduct inspections, education and compliance assistance. County counsel confirmed that local jurisdictions may only make maps more stringent than the state map; they may not reduce mapped hazard levels.

Vote and next steps: The board voted to introduce and express intent to adopt the local ordinance that will formally adopt the updated LRA hazard maps and enable enforcement of the applicable building, defensible‑space and access standards. The county reported it will coordinate implementation with municipal jurisdictions and provide public information about how residents can find their parcel on the State Fire Marshal—s mapping tool.

Speakers in this item included Fire Marshal Jason Downs and CAL FIRE/Napa County Fire Chief Matt Ryan; the board requested county communications to publish the state map link and instructions so property owners can confirm whether their parcel falls into a newly mapped zone.