Distance to nearest fire station
If an area is closer to a fire station, there is a greater likelihood that suppression equipment and personnel will arrive at a newly detected ignition in time to extinguish it before it becomes a problematic event. Sometimes wildfires gain momentum too quickly for even the closest fire stations to be effective, and sometimes fuel and weather conditions make rapid response futile. However, being close to a fire station is generally better than being farther away.
Fire station distance is calculated along roads, using fire station and road data from Precisely.
Distance to nearest water source
Another factor that can support suppression efforts is the presence of a water source. Streams, lakes, and ponds can be used by firefighters to fill trucks and helicopters with water to control the spread of a wildfire. Water features larger than 2 acres are identified as usable water sources. The value for this factor is based on the how far away the water source is.
Water data is source from the USGS National Hydrography Dataset.
Topographic position index
Fire travels uphill in the absence of wind. Topographic positions that have a lot of area below them for a wildfire to approach with momentum (ridges, for example) will have more risk to structures located on them than locations such as valley bottoms, which are below the majority of surrounding terrain.
Wildfire Risk Extreme uses the Topographic Position Index to separate the landscape into 10 different types, each of which is evaluated for its potential contribution to wildfire risk. Input data is sourced primarily from LANDFIRE.
Burnable percent
Not all of a landscape is covered with burnable fuels. The balance of burnable fuels and non-burnable material can have a mitigating or exacerbating effect on the risk of wildfire. Wildfire Risk Extreme examines the landscape within 0.25 miles of each polygon and looks for the combined percentage of burnable fuels versus non-burnable mitigation elements, such as:
- Agriculture
- Mitigation treatments
- Open water
- Bare ground
- Golf courses
More points are assigned if a landscape has a greater percentage of burnable area within a quarter-mile radius.
Burnable fuel data is provided by USDA Cropscape2, CALFIRE, and LANDFIRE