A Western United States Fire Climatology

Individual fire reports from the California Department of Forestry, the Bureau of Land Management, and the USDA Forest Service will be merged into one comprehensive fire data set for the western United States (WUSFire). The time period covered by this new data set will be 1981 - 1999. Gridded monthly fire starts and acres burned will be used to describe a seasonal fire climatology as well as intraseasonal and interannual variability. Indices describing modes of interannual variability will be related to contemporaneous and lagged climate as described by sea surface temperature, sea level pressure and precipitation.

Longer time series of annual fire starts and acres burned available from the Forest Service and aggregated by state from 1917 to 1999 will be analyzed in parallel with the better resolved WUSFire to identify common modes of variability. These representative modes derived from the longer data set will be examined for links to low-frequency climate variability. From preliminary analysis based on partial data, we anticipate that both the midlatitude and tropical Pacific climate should be related to fire patterns in the western US with decadal time scales residing in the North Pacific and interannual scales in the tropics. This research is part of a larger project to assess the long range predictability of fire weather in the Western United States.