SANTA ROSA, Calif. >> Storms brought rain to California today and increased the risk of mudslides in fire-ravaged communities, driving property owners to stack sandbags in devastated northern wine country and authorities to order evacuations farther south for towns below hillsides burned by the state’s largest-ever wildfire.

Forecasters issued a flash flood watch for parts for Sonoma and Mendocino counties north of San Francisco and warned that heavy rainfall could trigger mudslides in those areas devastated by October wildfires. The blazes leveled entire neighborhoods, killing 44 people and destroying more than 8,900 homes and other buildings.

A yearslong drought eased in California last spring, but Northern California had a dry start to winter and hardly any measurable rain has fallen in the south over the past six months. The extremely dry conditions and high winds last year led to some of the most destructive blazes on both ends of the state.

Now, the storm coming in from the Gulf of Alaska could dump up to 4 inches of rain on Northern California areas still recovering from fires before clearing up by Tuesday evening, National Weather Service meteorologist Steve Anderson said.

“Everything is soaking into the ground at this time, but if it gets very heavy, it could trigger a flash flood warning,” Anderson said.

In Southern California, about 21,000 people have been evacuated from neighborhoods beneath hillsides laid bare by the state’s largest-ever wildfire and other recent blazes amid fears of flash floods and debris flows.

Robert Lewin, director of the Santa Barbara County Office of Emergency Management, urged residents of Summerland, Carpinteria and Montecito to leave by midday. The hillside communities were evacuated last month as the massive Thomas Fire raged. Evacuations also include homes near other burn areas dating to 2016.

“Creeks that normally would be dry would turn into raging rivers of mud and debris and large rocks and trees,” Lewin said. “These can be quite damaging. They’ll destroy roads, they’ll take out homes.”

The wet and windy system moving ashore could soak much of the state and drop several inches in parts of Santa Barbara and Ventura counties, where the biggest-ever California blaze has burned for more than a month. About an inch of rain is forecast for downtown Los Angeles, the most in nearly a year.

In the foothills just northeast of Los Angeles, residents placed sandbags outside houses that survived a December fire that scorched more than 24 square miles, destroyed 60 homes and damaged 55 others.

“I’m on adrenaline right now. I was for a whole week during the fires, and this is just as — it’s a similar feeling,” Kat Pierson told LA news station KCAL-TV.

As the storm moved in early Monday, it snarled traffic in the San Francisco Bay Area during the morning commute and caused several crashes. No major injuries have been reported.

The National Weather Service also issued a winter weather advisory for portions of the Sierra Nevada above 7,000 feet (2,134 meters), forecasting about 4 to 7 inches of snow and up to 1 to 2 feet on higher peaks Tuesday. It says travelers should prepare for difficult travel conditions, including gusty winds, low visibility and slick and snow-covered roads.