A Pacific storm was beginning to drizzle across the Los Angeles area Wednesday night after dropping an inch or more in Northern California.
The system, which was expected to drop moderate rainfall beginning early Thursday, was the first of two storms that could cause mudslides in burn areas and lead to high winds, thunderstorms and big waves along the coast, the National Weather Service said.
"Waves of rain will last all night and into tomorrow morning," National Weather Service meteorologist Joe Sirard said Wednesday night.
The storm is expected to drop about a half-inch of rain in downtown Los Angeles and one to two inches in foothill and mountain areas. Up to 2-1/2 inches could fall on south slopes, where moisture-filled clouds will collide with the mountains and "squeeze out a little extra" rain, Sirard said.
He said the second storm "should come in very strongly" early Friday and drop one to 3 inches along the coast and in the valley areas. From three to six inches could fall in the mountains, and up to eight inches could drench south slopes, according to the weather service.
That could create potential life-threatening conditions from mudslides in fire-scarred hillside communities in the San Gabriel and Antelope valleys, officials said.
Fire stations across Los Angeles County were handing out sandbags, and county work crews were working to clear storm drains and set up barricades to channel mud flows away from homes. For a storm and mud-flow check list, click on the county Department of Public Works website.
"The biggest concern we have is the burn areas," Sirard said. "It could be life-threatening."
The second storm could cause winds in excess of 60 mph in mountain areas and waves from 10 to 15 feet at Southern California beaches, according to forecasters. Snow levels will drop to about 6,500 feet. The system is expected to move out of the region by Saturday night.
The wet weather is not expected to do much to alleviate drought conditions in Southern California because the rain will be soaked up by dry soil before percolating into the ground.
"We're not going to lose the drought because of this," Sirard said. "It will fill some of the reservoirs a little bit but not a whole lot."