Wildfires have scorched at least 5 million acres in the U.S. in 2018. In 2010, the total acreage was just over 3.4 million for the entire year. Experts say this reflects a trend, as wildfires have been burning larger swaths of land from year to year.
Shawna Legarza, who leads the USDA Forest Services’ Fire and Aviation Management department, says the increase may be due to the fact that wildfire "seasons" are getting longer; now, blazes burn nearly year-round.
"When I was first hired, it was sort of a seasonal job: Fires happened in different parts of the country in a particular time of year," Legarza said. "What I've seen since 2011 — fires have started to burn outside of their typical monthly time period."
Legarza has worked in wildfire management for 30 years, and she says she has observed an increase in acreage burned from year-to-year since the mid-1990s. Data from the U.S. Geological Survey support Legarza's observation: USGS measurements from 2006 forward show an uptick in acres burned and an increase in year-round occurrence of wildfires.
Legarza explained that there are three elements that determine wildfire behavior: fuels, weather and topography. Officials call it "the fire triangle."
While the U.S. has a robust inter-state wildfire response system, Legarza said the lengthening fire seasons are leaving state agencies "tapped out."