The Fire Hazard Severity Zone (FHSZ) model looks at two main things:

1. How likely an area is to burn
2. How a fire would behave under extreme conditions (strong winds, dry vegetation, and hot weather)

The zones group areas with similar wildfire risk based on factors like:

• Fire history (how often fires have happened there)
• Flame length (how intense the fire could be)
• Terrain (hills and slopes can make fires spread faster)
• Local weather (wind and temperature patterns)
• Potential fuel (trees, shrubs, and grass available to burn over the next 50 years)

Outside of wildland areas, the model also considers:

• Urban vegetation (trees and plants near buildings)
• Blowing embers (which can start new fires)
• How close buildings are to wildland areas
• Fire hazard levels in nearby wildlands

Important: The FHSZ map does not predict how much damage a fire might do to homes and buildings. It focuses on wildfire behavior, but it does not include details about individual structures, such as roof type or fire-resistant materials.

Fire Hazard Severity Zones (FHSZ) help guide wildfire safety rules and planning. They are used to:

• Determine where defensible space laws and wildfire-resistant building codes apply.
• Inform real estate disclosures, so buyers know if a property is in a wildfire-prone area.
• Help local governments make land-use decisions and update their community plans.

The Fire Hazard Severity Zone (FHSZ) map shows hazard levels, not risk levels—similar to how flood zone maps indicate the likelihood of flooding in an area, rather than the specific damage it might cause.

• Hazard refers to the natural conditions that make wildfires more likely and predict how they might behave over a long period (30–50 years). This does not consider efforts like home hardening, past wildfires, or vegetation management.
• Risk refers to the potential damage a wildfire could cause under current conditions, factoring in safety measures like fuel reduction, defensible space, and fire-resistant construction.

The FHSZ map helps communities understand wildfire hazard levels, but actual risk depends on ongoing efforts to reduce fire threats in specific areas.

If your property is in a High or Very High Fire Hazard Severity Zone within a Local Responsibility Area, you need to follow certain wildfire safety rules:

• New buildings must follow California’s wildfire-resistant building codes (WUI codes, CBC Chapter 7A).
• Remodels may also need fire-resistant construction—check with your local building department for specific requirements.
• Defensible space is required by law (Government Code 51182), meaning you must clear vegetation around your home to reduce fire risk.
  • NOTE: If your property is located in a Very High Fire Hazard Severity Zone, you are required by law to include 100 feet of defensible space around your house or buildings on the property.
• If you sell your home, you must disclose if it’s in a fire hazard zone as part of the real estate process.

For more details on wildfire safety, defensible space, and home hardening, visit www.readyforwildfire.org.

A Fire Hazard Severity Zone (FHSZ) is an area identified by the State Fire Marshal as having a certain level of wildfire risk. These zones are classified based on factors such as:

• The amount and type of vegetation (fuel for fires)
• The steepness of the land (slope)
• Weather conditions that contribute to fires
• Strong winds that can spread wildfires

The State Fire Marshal categorizes these areas into three levels of fire hazard risk: Moderate, High, and Very High. These classifications help determine fire prevention and safety measures in different regions of the state.