Climate and predictability of Alaska wildfires

Abstract

Wildfires burn an average of 3,760km² each year in Alaska, but varies greatly from year to year. These fires, started by human and natural causes, can endanger life and property when they approach populated areas. The relationship between seasonal area burned and monthly and seasonal average mean sea level pressure, surface air temperature, total column precipitable water, 500hPa and 700hPa geopotential height, 700hPa specific humidity and 1000-500hPa layer thickness is examined. The assessment was done by examining the spring and summer seasonal composites associated with extreme high and low seasons. This showed the predominant anomalies from the climatology for seasons of both extremes. Point correlations were also made between seasonal area burned and the aforementioned climate variables for the entire Northern Hemisphere. Points of particularly high correlation with area burned were used in multiple regressions for both spring and summer, and for the preseason only to predict seasonal area burned. Results show correlations of about 0.78 for the preseason regression and 0.91 for the total period. The seasonal area burned in Alaska is intimately linked with the ongoing synoptic situation on monthly and seasonal scales before and during the fire season.