More, bigger wildfires burning Western U.S.

Wildfires across the western United States have been getting bigger and more frequent over the last 30 years – a trend that could continue as climate change causes temperatures to rise and drought to become more severe in the coming decades, according to new research by Geography faculty Philip Dennison and Simon Brewer, and former Master's student James Arnold.

The number of wildfires over 1,000 acres in size in the region stretching from Nebraska to California increased by a rate of seven fires a year from 1984 to 2011, according to a new study accepted for publication in Geophysical Research Letters

The total area these fires burned increased at a rate of nearly 90,000 acres a year – an area the size of Las Vegas. Individually, the largest wildfires grew at a rate of 350 acres a year, the new research says.

“We looked at the probability that increases of this magnitude could be random, and in each case it was less than one percent,” said Philip Dennison.

Looking at the ecoregions more closely, the authors found that the increase in fire activity was the strongest in the mountain regions of the United States: across the Rocky Mountains, Sierra Nevada, Arizona- New Mexico mountains; Southwest deserts; and southern plains across western Texas, Oklahoma, Kansas, and eastern Colorado. These are the same regions that would be expected to be most severely affected by changes in climate.

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Dr. Phil Dennison being interviewed by KSL reporter Jed Boal
(Credit: KSL)