A days-long heat wave rolling across parts of the US West is expected to ramp up wildfire risk, prompting California to pre-deploy crews as record-dry vegetation potentially acts as kindling for blazes.
Temperatures in Southern California are expected to spike into the 90s and 100s Fahrenheit (32-38 Celsius) by Thursday and remain stubbornly high into the weekend, possibly breaking daily temperature records in some areas, according to the US Weather Prediction Center. That heat -- combined with plummeting humidity and a chance of thunderstorms resulting from unstable air over nearby mountain ranges -- will create dangerous conditions for brush fires to start or spread.
"There's pretty high concern because vegetation in some spots is at record dry values for August," said Daniel Swain, a climate scientist with the University of California system, adding that grasses and plants that flourished during previous rainy winters in Southern California have gradually dried out over the past year.
Wildfires in the US West have been growing more intense as climate change triggers longer droughts punctuated by heavy rains that feed vegetation and raise the risk of mudslides on fire-scarred terrain. Southern California is still reeling from deadly fires in January, which destroyed thousands of homes in and around Los Angeles.
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Gov. Gavin Newsom said in a statement that he has directed California's Office of Emergency Services to dispatch fire engines, helicopters, bulldozers and firefighting crews to stand by in five counties, including Los Angeles and Ventura, in case a blaze erupts during this week.
Crews have already battled numerous brush fires in the Los Angeles area this month, including one that forced evacuations and consumed more than 130,000 acres. While brush fires can occur year-round in Southern California, they typically peak in early fall.
Beyond California, intense heat is also expected to set in across the US Southwest and High Plains. Daytime temperatures could reach 10F to 15F above normal with little cooling overnight, said Zack Taylor, a meteorologist with the US Weather Prediction Center. Daytime highs are set to reach 112F (44C) in Phoenix and 110F (38C) in Las Vegas.