Fire Hazard of Every Building in California: An Interactive Map

Recent wildfires in Southern California, most notably the Saddleridge Fire in the San Fernando Valley and the Sandalwood Fire in Riverside County, serve as reminders that many communities in the state are vulnerable to wildfire hazards.  While all Californians should be adequately prepared for disasters such as earthquakes and wildfires, some communities are more vulnerable to wildfires than others.

UCLA Geospatial developed the following interactive map showing all buildings in California, as classified by the CAL FIRE Fire Hazard Severity Zone to which each building belongs.

Search for your address, the name of your community, or the address of any building in California -- or just browse the map to explore fire hazard statewide.  Please note that by using the map below, you agree that you are using the map exclusively for educational and/or informational purposes.

Using the Map

You may search for any address or location within the state of California using the search box at the top right corner of the map.  Hovering over any building will trigger a pop-up information box that will display the fire hazard severity zone within which the building falls, as well as the type of firefighting agency that is responsible for providing primary firefighting in the area (Local, State, or Federal.)

About the Data and the Fire Hazard Classifications

CAL FIRE (California Department of Forestry and Fire Protection) is the state's primary statewide firefighting agency.  In 2007, CAL FIRE classified areas within its state firefighting responsibility area (SRA) as belonging to one of several fire hazard severity classifications:  moderate fire severity hazard (yellow on map), high fire severity hazard (orange), very high fire severity hazard (red), and unzoned (gray).  Maps of these fire hazard zones have been published on CAL FIRE's website, along with the corresponding GIS data used to generate the maps.  Additionally, while CAL FIRE is responsible for designating fire hazard zones only within its firefighting responsibility areas, the agency also published maps and GIS data delineating the fire hazard severity zones that it recommended to local and federal firefighting agencies.

The fire hazard classifications visible on this map are derived from merging CAL FIRE's adopted fire hazard severity zones within its SRA with all of the recommended fire hazard zones that CAL FIRE presented to local and federal authorities.

It is important to emphasize that the recommended fire hazard severity zones that CAL FIRE presented to local and federal authorities were merely recommendations -- local and federal authorities were free to adopt and implement different definitions of fire hazard severity zones, and many did implement different maps of fire hazard zones.  Given the number of relevant local and federal agencies within California and the challenge of collecting usable data from every such agency, we opted to display the CAL FIRE recommendations rather than the actual adopted fire hazard zones for local and federal responsibility areas.  We recommend contacting any relevant local and federal agencies for more information about officially adopted fire hazard zones in LRAs and FRAs. 

Of course, the fire hazard severity zones published by CAL FIRE represent the agency's assessment of overall fire hazard and severity.  Destructive wildfires have been observed in areas of California that did not fall into high or very high fire hazard severity zones, so this map is meant to be used as a general reference rather than a definitive determination of any structure's actual fire hazard.

We would also like to emphasize that in developing this map, UCLA Geospatial is neither determining nor offering any opinion on the actual fire hazard to which any property or structure is subject, and UCLA Geospatial has no control over determining the fire hazard zones presented in this map -- this is the responsibility of CAL FIRE and other responsible agencies. This map simply presents public data from CAL FIRE in overlay with a dataset that shows approximate building footprints.  This map is to be used for educational and informational purposes only and we specifically advise against using this map for any other purposes.  UCLA Geospatial is not able to respond to individual requests for reclassification of fire hazard of properties, structures, or areas since the fire hazard severity zones used to create this map originated from CAL FIRE.

Footprints for buildings within California were obtained from Microsoft's U.S. building footprints dataset, which includes nearly 11 million structures within California.

About the GIS Methods and Web Mapping Technologies

This map was developed entirely using free and open source software, including QGIS, Mapbox GL, Tileserver GL, and a Web server running a variant of Linux.

QGIS, a desktop GIS software platform, was used to merge CAL FIRE's SRA fire hazard zones with recommended local responsibility area (LRA) fire hazard zone classifications for each county individually.  We also used QGIS to perform basic processing of Microsoft's building footprint data prior to the execution of a spatial join which was used to identify the primary fire hazard zone to which every building in California belongs.

Mapbox GL JS is a Web mapping library that allows for the display of complex spatial data directly within Web browsers using hardware-accelerated graphics rendering.  Mapbox GL is used to render both the building footprint data as well as the basemap data.  Mapbox GL JS also is used to access Mapbox's geocoding service, which allows users to search for addresses and place names.

TileServer GL is used to serve and transmit tiled vector basemap and building footprint data.  The vector basemap data hosted by TileServer GL is drawn from the OpenMapTiles project, which provides free access to pre-generated vector tiles of OpenStreetMap data.

GDAL/OGR was used to generate a vector MBTiles file of California building footprints, allowing for the massive dataset to be rendered quickly by Mapbox GL JS at any geographic scale.