WUI Maps / Fire Hazard Severity Zones

The Wildland Urban Interface (WUI), is the geographical area where structures and other human development meets or intermingles with wildland and vegetative fuels.   Properties located within the WUI are typically at increased risk from wildfires. 

Towns of Fairfax, Ross, San Anselmo, and Sleepy Hollow Fire Protection

The Towns of San Anselmo, Fairfax, and Ross, and unincorporated Sleepy Hollow, have adopted the 2025 California Fire Code and the 2025 California Wildland Urban Interface Code with amendments.  To determine whether your home is in the WUI and/or Fire Hazard Severity Zone please review the Ross Valley map below. 

To use the map click the magnifying glass in the upper left corner and enter your address. To view the legend click the icon with 4 lines, this will be the icon under the magnifying glass. 

 

About each map: 

The Fire Hazard Severity Zone (FHSZ)

These 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 on these maps: moderate, high, and very high.  Fire Hazard Severity Zone maps evaluate “hazard,” not “risk”. They are 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. 

For more information on Fire Hazard Severity Zone maps visit: https://osfm.fire.ca.gov/what-we-do/community-wildfire-preparedness-and-mitigation/fire-hazard-severity-zones

The Wildland Urban Interface (WUI)

These WUI maps, is the geographical area where structures and other human development meets or intermingles with wildland and vegetative fuels. Properties located within the WUI are typically at increased risk from wildfires.  California is the #1 state in the US with the greatest number of houses in the WUI, relative to the total houses in the state.  

Questions about the LRA maps can be directed to Ross Valley Fire Department: 777 San Anselmo Avenue, San Anselmo. Email comments that are applicable to the Ross Valley Fire jurisdictional boundaries to prevention@rossvalleyfire.org or call the Prevention Bureau at (415) 258-4686, ext 5.