Fire-Scarred Areas Brace for Storms, Flash Floods

The Bay Area is bracing for an “atmospheric river” — a massive, fast-moving storm system expected to soak the region this weekend.

The weather event could bring up to seven inches of rain to Sonoma County alone. In response, officials there are lowering the inflatable rubber dam in the Russian River to prevent damage when the water rises.

"It's unusual in that this is a large, atmospheric river for this early in the season,” said Barry Dugan, a spokesperson with Sonoma Water. “We normally see them a little bit later. What these atmospheric rivers do is they carry a tremendous amount of moisture into the area.”

Aside from lowering the dam, Dugan said there isn't much additional preparation. "We don't expect that the river is going to reach a flood stage," he said.

While he doesn’t expect the river to overflow, meteorologists have issued a flash flood watch for areas scarred by wildfires.

The community and emergency personnel are putting out the alert for people to prepare for debris flows, and in San Francisco, San Mateo County and elsewhere, officials are offering free sandbags to reduce flood damage.

The National Weather Service for the San Francisco Bay Area issued a high surf advisory through Friday for a portion of the coast and a flash flood watch Sunday for parts of the region, especially in areas burned by last year’s wildfires. Strong winds also are expected Sunday, with gusts of up to 60 mph at the windiest spots.

The weather service said elevations above 9,000 feet in the Sierra Nevada could get 18 inches of snow or more from Sunday until Monday morning and warned of possible power outages and road closures.

Mike Pierre, owner of Mission Ace Hardware and Lumber in Santa Rosa in Sonoma County, said they sold out of tarps this week and expect to do so again in advance of Sunday’s big storm.

But there is a feeling of relief that the area could escape wildfire this year, unlike last year when the Glass Fire broke out in late September and destroyed nearly 1,600 homes and other buildings. Customers had been stocking up on generators and power cords to prepare, Pierre said.

“People were bracing for that, and it never happened,” he said, “and hopefully, this rain will keep it from happening.”

But burn areas remain a concern, as land devoid of vegetation can’t soak up heavy rainfall as quickly, increasing the likelihood of mud or debris slides and flash flooding.

Paul Lowenthal, an assistant fire marshal with the Santa Rosa Fire Department in Sonoma County, said the city is providing free sand and bags for residents who need to control rain runoff. They are also asking residents to clear gutters and on-site storm drains as the city prepares for up to 6 inches of rain.

“Given the volume of water we’re expecting, we want it to go where it needs to go,” he said.

Parts of western Santa Barbara County were under an evacuation warning Friday night in the area that had been burned by the Alisal Fire. The blaze charred 26.5 square miles and is 97% contained. The fire erupted in the Santa Ynez Mountains during high winds on Oct. 11.

Californians rejoiced when rain started falling this week for the first time in any measurable way since spring. NWS Bay Area tweeted that San Francisco International Airport set a record rainfall for Thursday, with 0.44 inches of rain. The old record was 0.13 inches on the same day in 1970.

Rain and snow will continue soaking Central and Northern California before spreading into Southern California on Monday.

The storms have helped contain some of the nation’s largest wildfires this year. But this week’s storms won’t end drought that’s plaguing California and the western United States. California’s climate is hotter and drier now and that means the rain and snow that does fall is likely to evaporate or absorb into the soil.

California’s 2021 water year, which ended Sept. 30, was the second driest on record, and last year’s was the fifth driest on record. Some of the state’s most important reservoirs are at record-low levels. For example, state officials say Lake Mendocino could be dry by next summer.

This post includes additional reporting from KQED's Holly J. McDede and The Associated Press.