Fire Hazard Severity Zones (FHSZ)

California state law requires the California Department of Forestry and Fire Protection (CAL FIRE) to identify and map fire hazard areas statewide, referred to as "Fire Hazard Severity Zones.” On March 24, 2025, CAL FIRE released an updated version of the map from the director of CAL FIRE for an updated Fire Hazard Severity Zone (FHSZ) map in the City of Laguna Niguel. These maps use the latest climate data, fire history, topography, and wildfire modeling to classify areas as Very High, High, or Moderate Fire Hazard Zones. 

While local governments, including the City of Laguna Niguel, do not determine the contents of the FHSZ maps, they are required by state law to make the updated maps available for public review and comment, and to adopt these designations within 120 days. Although cities may not reduce a fire hazard severity designation, discretion is provided to cities to increase a designation where appropriate based on community input and local risk assessments. On June 3, 2025, the City Council adopted the updated state-mandated FHSZ ordinance. 

What are Fire Hazard Severity Zones?

The Fire Hazard Severity Zone (FHSZ) maps are developed using a science-based and field-tested model that assigns a hazard score based on the factors that influence fire likelihood and fire behavior. Many factors are considered, such as fire history, existing and potential fuel (natural vegetation), predicted flame length, blowing embers, terrain, and typical fire weather for the area. There are three levels of hazard in the Local Responsibility Areas: Moderate, High, and Very High. The map below shows the updated fire hazard severity zones in Laguna Niguel. Residents can utilize the interactive map by entering their address and view their designated fire hazard severity zone. 

How do the updated maps impact my property?

Properties located within the Fire Hazard Severity Zones are required to comply with the following items to reduce the chance of building loss or damage from a wildfire: 

FHSZ Examples of Requirement Graphic - Revised April 2025

Frequently Asked Questions

Several frequently asked questions are answered below, and a comprehensive FAQ sheet from CAL FIRE can be accessed here.

How are fire hazard severity zones determined?

CAL FIRE uses the best available science and data to develop and field-test a model that serves as the basis of zone assignments. The model evaluated the probability of the area burning and potential fire behavior in the area. Many factors were included, such as fire history, vegetation, flame length, blowing embers, proximity to wildland, terrain, and weather.

What do fire hazard severity zones measure?

The Fire Hazard Severity Zone map evaluates “hazard,” not “risk.” The map is like flood zone maps, where lands are described in terms of the probability level of a particular area being inundated by floodwaters and not specifically prescriptive of impacts. “Hazard” is based on the physical conditions that create a likelihood and expected fire behavior over a 30 to 50-year period without considering mitigation measures such as home hardening, recent wildfire, or fuel reduction efforts. “Risk” is the potential damage a fire can do to the area under existing conditions, accounting for any modifications such as fuel reduction projects, defensible space, and ignition-resistant building construction. 

What are the key elements of the fire hazard severity zone model?

The fire hazard severity model for wildland fire has two key elements: the probability of an area burning and expected fire behavior under extreme fuel and weather conditions. The zones reflect areas that have similar burn probabilities and fire behavior characteristics. The factors considered in determining fire hazard within wildland areas are fire history, flame length, terrain, local weather, and potential fuel over a 50-year period. Outside of wildlands, the model considers factors that might lead to buildings being threatened, including terrain, weather, urban vegetation cover, blowing embers, proximity to wildlands, fire history, and fire hazards in nearby wildlands. FHSZs are not a structure loss model, as key information regarding structure ignition (such as roof type, etc.) is not included.

Why are the fire hazard severity maps being updated?

The hazard maps are being updated to more accurately reflect the zones in California that are susceptible to wildfire. The hazard mapping process will incorporate new science in local climate data and improved fire assessment modeling in determining hazard ratings.

Can the City change the fire hazard severity zone map?

No. The City can only increase the level of fire hazard severity as identified by CAL FIRE for any area within the jurisdiction. Fire hazard severity cannot be decreased by the City.

How will the updated Cal Fire Maps affect insurance availability and affordability?

According to the California Department of Insurance, CAL FIRE maps are intended to drive local planning decisions, not insurance decisions. Under the California Department of Insurance's new regulation finalized in October 2022, insurance companies must provide discounts for wildfire safety actions such as community mitigation and home-hardening, which CAL FIRE’s maps do not assess. In addition, insurance companies are already using risk analysis tools and models that go beyond CAL FIRE’s proposed maps in determining what properties they will underwrite. Additional information from the California Department of Insurance can be accessed here. 

Other Resources