WILDFIRE PATTERNS AND SUSCEPTIBILITY AT THE WILDLAND-URBAN INTERFACE IN CALIFORNIA

Increasing population and expanding development has resulted in more fire ignitions and influenced suppression policies, exacerbating conditions at the wildland-urban interface (WUI) across the western U.S. The current study investigates historical wildfire size and frequency relative to the WUI for a range of counties within California. Geospatial mapping of fire ignition locations show the tendency of wildfire occurrence patterns to follow transportation corridors and development, directly accelerating mitigation and insurance costs. California’s fire frequency and total acres burned exhibit increasing trends (statistically significant at 95%). The 1980s average wildfire frequency and total acres burned was 3100 fires and 300,000 acres, respectively. These numbers have increased to 2200 fires and over 360,000 acres in the 2010 to 2012 period, respectively. Further analysis shows decennial population and acres burned for four major Californian counties (Los Angeles, San Bernardino, San Diego, and Shasta) have high correlation between the last decade of burned area, urban-fringe proximity, and urbanization trends. Our study will provide information on urban fringe communities most vulnerable to the risks associated with wildfire and post-fire impacts. In light of evolving land use policies (i.e. forest management and treatment and development at the urban-fringe) and climate change, it is critical to advance our knowledge of the implications that these conditions pose to urban centers, communicate risks to the public, and provide guidance for post-wildfire mitigation.