Power failures caused by the weather blacked out about 20,000 homes and businesses around the state. Two traffic deaths were linked to the storm.
At higher elevations, heavy snow in a mountain pass east of Los Angeles closed the main route connecting Las Vegas to Southern California. North of the city, the main route to San Francisco was snarled by snow that forced the state Highway Patrol to shepherd motorists over another pass in caravans.
The rain apparently collapsed the roof of a classroom at the North Orange County Regional Occupational Program building in Anaheim. Seven people were taken to a hospital, said police Sgt. Rick Martinez. Their conditions were not immediately available.
Roughly 150 students were at the center, which prepares high school students and adults for medical occupations, said spokeswoman Pat Hansmeyer. Only three of the students were minors, and they were not injured, she said.
Yorba Linda, where 100 homes were lost to a wildfire last month, hundreds of homes in canyon areas on the east end of town were ordered evacuated Monday morning because of the threat of mudslides. Residents had been advised to leave as early as Sunday night, and an evacuation center was opened.
"It is mandatory now, unknown duration," said Brea police Lt. Jim Tibbetts.
The wildfires had stripped hillsides of vegetation. Muddy runoff on some roads was reported near midday.
The storm was part of the same weather system that brought heavy snow to Portland, Ore., on Sunday, snarling traffic and delaying airline flights, said Steven Van Horn, a National Weather Service meteorologist.
In Northern California, about 8 inches of heavy snow brought down tree limbs on power lines, blacking out more than 11,000 customers in the Grass Valley area, Pacific Gas & Electric spokesman Paul Moreno said.
Rainfall totals for Southern California on Monday morning ranged from more than 1 inch at Moorpark to more than 2 inches at the Gibraltar Dam in Santa Barbara County. Snow fell at areas above 3,000 feet. The Lockwood Valley in the mountains of Ventura County had 8 inches by midmorning.
The storm was expected to linger in the area through Wednesday, Van Horn said, although showers were expected to be scattered and lighter on Tuesday and Wednesday.
Among the deaths linked to the storm, a California Highway Patrol officer directing traffic around a vehicle that wrecked in the rain in Hacienda Heights, east of Los Angeles, was hit by another car that went out of control, said patrol Officer Terry Liu. In the San Diego area, one person was killed when an armored truck slid off a wet highway and rolled down an embankment.