High-Resolution Future Projection of U.S. Wildfire Potential Trends

Recent extreme wildfires in the U.S. have cost the country hundreds of millions of dollars each on direct and indirect costs. It is anticipated that climate change could lead to a higher frequency of these costly fires. In order to analyze the location and magnitude of this increase, the Keetch-Byram Drought Index (KBDI), used for wildfire risk assessment by both the USFS, and the U.S. military, is calculated for the continental United States and Alaska using high resolution daily precipitation and maximum temperature data from both observation and model output. Utilizing model output, the KBDI was calculated for mid and end of century time periods in addition to historical scenarios. An initialization method for the KBDI was developed to increase its usefulness in dry areas of the country. Results show that the index will rise in all regions; the greatest increases in the frequency of high KBDI events occurs in the Southwest, South Great Plains, Northwest, and Southeast during the summer and fall. The relative importance of temperature and precipitation are investigated, and it is shown that temperature change is the main contributor to the index increase.