(Bloomberg) -- Exceptionally powerful, dry winds expected across Southern California this week are set to send wildfire risk skyrocketing in a region that’s endured more than eight months without significant rain.
Forecasters predict the strongest Santa Ana wind event of the season will start Tuesday and extend late into the week. As offshore winds race down local mountain ranges, they’ll bring gusts of up to 80 miles (129 kilometers) per hour to densely-populated communities in Los Angeles and Ventura counties, putting more than 4.5 million residents at risk, according to the US Storm Prediction Center. Downtown Los Angeles hasn’t seen more than a half-inch of rain since April, according to National Weather Service data.
“This is one of those patterns that make the hair stand up a little bit,” said climatologist Daniel Swain at the University of California Los Angeles, who called the event an “atmospheric blow dryer.” The winds, he said Monday, would be strong enough to topple trees and power lines, block roads, trigger blackouts and cancel flights at airports. “This will probably affect more people more substantially than a major rainstorm.”
In a post on X Monday, forecasters for the National Weather Service in Los Angeles warned of “life-threatening, destructive” winds in areas not typically affected by Santa Ana events. Some of the region’s most affluent and exclusive communities — such as Beverly Hills and Malibu — are included.
In some mountain passes and foothill communities, gusts could reach 100 mph, drying the air and pushing humidity levels as low as 4%, said Nick Nauslar with the US Storm Prediction Center.
“That’s going to continue for two, three, perhaps four days,” said Nauslar, the center’s fire weather science and operations officer. With this combination of factors, he said, “you’re getting into the upper echelon of Santa Ana wind events in the last couple decades.”
Months without rain have parched the Southern California landscape, leaving dry grasses, shrubs and trees that can fuel wildfires. The amount of moisture stored inside local vegetation — which can prevent it from burning — is now “well below normal and approaching record low for this time of year,” Nauslar said.
Red flag fire warnings have been issued for much of the Los Angeles area and its suburbs. But high winds will extend far beyond the city, with strong gusts expected from Shasta County in far northern California all the way to the Mexican border. Wind advisories were also posted for the hills above the San Francisco Bay Area wine country, which has suffered a series of devastating fires in recent years.
California’s electric utilities have already warned power shutoffs may be needed to prevent electricity lines from sparking wildfires that could quickly grow out of control. Edison International’s Southern California utility warned 294,369 homes and businesses in six counties could lose power. Sempra’s San Diego Gas & Electric utility said it had warned 64,866 customers of potential outages.
Such shutoffs usually affect rural areas or suburbs. But climatologist Swain said this week’s Santa Ana event would even bring damaging winds to Southern California’s urbanized valley floors and cities. “There are more potential ignition sources, and it’s also harder to shut off the power preemptively,” he said.
Listen on Zero: The 21st Century Will Be Shaped by Destructive ‘Fire Weather’
(Adds comments from UCLA climatologist Daniel Swain in paragraphs three and 10.)
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