Jayson Coil

The 2011 Las Conchas fire burned more than 150,000 acres in New Mexico’s Jemez Mountains.Jayson Coil

Summer is coming and in the Western U.S., from California to Nebraska, summer means fire season. New research shows an upward trend in the number of wildfires over the past 30 years, a trend fueled by growing drought in Western states.

A team based at the University of Utah used satellite images to tally wildfires that burned more than 1,000 acres over the past 30 years in 17 states west of the Mississippi. By their count, the number of large fires increased, on average, by seven per year between 1984 and 2011.

The total area burned increased by an average of 90,000 acres per year, an area roughly the size of Las Vegas, according to the researchers.

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"Twenty-eight years is a pretty short period of record, and yet we are seeing statistically significant trends in different wildfire variables -- it is striking," says study co-author Max Moritz of the University of California, Berkeley, in a release.

Researchers noted that increased fire activity hit mountain regions and the desert Southwest -- from California to Texas -- particularly hard. New Mexico, a state containing both regions, saw more than a thousand wildfires last year that consuming more than 220,000 acres. In March, the Silver Fire in New Mexico’s Gila National Forest kicked off this year’s fire season with a bang, scorching more than 138,000 acres.

Wildfire trends are in line with forecasts of climate-change-related drought in the West, the researchers write in Geophysical Research Letters, which published their results. Yet other factors may be exacerbating fire intensity.

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Past forest management practices that suppressed fires and allowed fuel supplies to build up may also be to blame, says U.S. Geological Survey ecologist Jeremy Littell in a release.

“It could be that our past fire suppression has caught up with us,” said Littell, who was not involved in the study. “It could also be a response to changes in climate, or both.”