Extreme Fire Season in California: A Glimpse into the Future


Under continuous drought conditions since 2012, California’s drought considerably worsened in the winter of 2013–2014. This change fueled an extreme fire season in 2014. Using the satellite-retrieved burned area and the index indicating extreme fire risk, scientists at Pacific Northwest National Laboratory and Utah State University found that the 2014 fire season is the second largest in terms of burned area in northern California since 1997 (second only to 2012), and stands the highest since 1979 in rankings of extreme fire risk over the entire state. The research used the Keetch-Byram Drought Index (KBDI) based on the historical observation and multi-ensemble simulations of the Community Earth System Model (CESM). Measures of extreme fire risk are also expected to increase in the future despite an overall lack of change in the mean fire probability and annual precipitation, as simulated by CESM for the next 50 years. Manmade global warming is likely one of the causes that will exacerbate the areal extent and frequency of extreme fire risk, though the influence of internal climate variability on the 2014 and future fire season is difficult to ascertain.



Yoon, J.-H., S.-Y. S. Wang, R. R. Gilles, L. Hipps, B. Kravitz, and P. J. Rasch. 2015. “Extreme Fire Season in California: A Glimpse into the Future?” In “Explaining Extremes of 2014 from a Climate Perspective,” Bulletin of the American Meteorological Society 96(12), S5–S9. DOI: 10.1175/BAMS-D-15-00141.1.