The National Weather Service forecasts widespread soaking rain across Northern California this weekend, which is expected to give the region a temporary respite from the drought-fueled threat of wildfires.
But strong winds sweeping through Northern California ahead of the storm could also make things harder for firefighters working to contain the Mosquito Fire west of Lake Tahoe.
Meteorologists expect colder temperatures and precipitation, including 1 to 2 inches of rain for much of the Bay Area — likely beginning Sunday morning — with more falling in the North Bay.
Experts say the precipitation couldn’t come at a more crucial time: California's forests are critically dry after an extended heat wave. Northern California fire agencies are calling the upcoming storm "a significant fire season slowing event."
In Placer and El Dorado counties, where the Mosquito Fire has grown to nearly 70,000 acres and remains 20% contained, the weather system is expected to bring anywhere from 1/4 inch to more than 1 inch of rainfall over several days.
However, stronger winds are also expected to arrive in the area beginning Saturday, and the winds could throw burning embers and create spot fires. That would be a setback for firefighters working to contain the week-old, nearly 106-square-mile blaze, which on Wednesday became the largest in the state so far this year.
The weekend's forecast is "a bit of a mixed blessing here," Fire Behavior Analyst Jonathan Pangburn said Thursday.
The forecast came as firefighters again prevented flames from entering a mountain town and reported major progress Thursday, just two days after the fire roared back to life and burned structures near Foresthill. Crews on the ground built up containment lines while water-dropping helicopters knocked down hotspots.
Conditions on the ground Thursday were "looking a whole heck of a lot better," according to fire spokesman Scott McLean.
"It's looking really good on the west end where we had that dramatic increase of fire earlier this week," McLean said Thursday. Flames raced up a drainage ditch into a neighborhood, but firefighters saved all the homes. Evacuation orders remained for some 11,000 residents because of the unpredictable nature of the winds, McLean said, which typically blow in the direction of several canyons and could rapidly spread flames if gusts pick up.
Scientists say climate change has made the West warmer and drier over the last three decades and will continue to make weather more extreme and wildfires more frequent and destructive. In the last five years, California has experienced the largest and most destructive fires in its history.
This weekend's rain is forecast to be a one-off event, said meteorologists, and likely won’t produce enough moisture to end this year's fire season.
"We still have another month and a half before we might be seeing a regular progression of storms — assuming that's going to happen this year," said Jan Null, an adjunct professor of meteorology at San Jose State University. "In the interim, October through early November, is when we start seeing our Diablo winds here."
Those autumn wind events have been a key factor in recent wildfire disasters in the Bay Area, including the North Bay fires of 2017, the Kincade Fire in 2019, and the Glass Fire in 2020.
"Unless we get more storms after this one, things are going to dry back out in a week or two," Null said. "The forests and wildlands are in such dry condition that this will put a temporary hold on things but not end the season."
KQED's Dan Brekke and Kevin Stark contributed to this report.
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