Just days before the fire erupted, scientists reported findings showing an increase in large wildfires may be linked to global warming. According to their research, the rise in temperatures was the most important factor in a four-fold increase in the number of Western wildfires since 1970. From 1987 to 2003, average spring and summer temperatures were more than one and a half degrees higher than they were during the previous seventeen years. The climate changes meant earlier springs, shorter winter snow, and drier forests. Last year was the worst wildfire season on record. This year, there have been more than 60,000 wildfires — twice the number during the same period last year. Thomas Swetnam, a fire specialist and research director at the University of Arizona, said: “I see this as one of the first big indicators of climate change impacts in the continental United States.”