A new study says that less summer precipitation, and longer summer dry spells, are major drivers of increased wildfire activity in the western U.S. It’s contrary to previous understanding that warming temperatures and earlier snowmelt are the only factors in bigger wildfire seasons.
The study by the U.S. Forest Service and University of Montana scientists was published this week in the Proceedings of the National Academy of Sciences.
Scientists found that summer precipitation totals and the length of dry spells were the strongest controls on wildfires.
Lead author Zack Holden says dry periods are closely related to how dry the air is during fire season.
The research team looked at the effects of snowmelt timing, warming summer temperatures, and differences in the amount and location of rain on wildfires.
The study was a part of a larger project aimed at improving wildfire danger and drought monitoring.