Fires are lasting longer into the night, and researchers may have found out why

 

https://www.washingtonpost.com/weather/2021/09/25/fires-burning-longer-night-west/

 

By Kasha Patel
September 25, 2021 at 8:12 a.m. EDT 

Firefighters in the western U.S. have noticed a disturbing trend in recent years: fires are intensifying earlier in the morning and burning longer into the night.

“Firefighters are still fighting the fire at 10:00 or 11:00 at night when historically they thought they could stop at 8:00,” said Brian Potter, a research meteorologist with the U.S. Forest Service at the Pacific Northwest Research Station. “What that means is the fire managers don’t get a break.”

Satellite data and ground reports indicate wildfire activity has increased at night in recent decades, meaning firefighters have less time to rest and regroup overnight. This year, the Caldor fire southwest of Lake Tahoe, which has consumed more than 220,000 acres as of Sept. 24, more than doubled overnight early on. The Windy fire also experienced significant overnight growth as it burned in the Sequoia National Forest.

Potter and his colleagues investigated why firefighters are seeing more nighttime fire activity now than at the beginning of their careers. In a recent study, they found air over most of the western U.S. has become drier and warmer at night over the past 40 years, influencing the rate at which vegetation and other fuels for fire will dry out and burn.

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