Southern California braces for rainfall

Hillside homeowners and emergency crews braced for heavy rain and mountain snow Sunday night as the first strong storm of the rainy season bore down on Southern California, prompting warnings of flash floods as well as possible mudslides in areas denuded by recent wildfires.

The heaviest rain in the Los Angeles metropolitan area was expected to fall from 10 p.m. Sunday until 10 a.m. today, with thunderstorms also possible. After morning, the chance of showers gradually decreases through Wednesday.

Total rainfall is expected to average up to 1.5 inches in coastal and valley areas, and 1.5 to 3 inches in the foothills. The heaviest showers are expected to dump rain at a rate of half an inch per hour.

People living next to burn areas should be especially watchful, said Los Angeles Fire Department spokesman Ron Myers. Those living next to burn areas in Orange County were placed under voluntary evacuation orders at 10 p.m. Sunday.

He advised them to survey their properties for areas where runoff is likely and to consider routes in and out of canyon locations. Myers also said swift-water rescue teams are on call, but he urged people to stay away from washes and storm drains.

Residents who put themselves at risk also endanger others, he said, adding that 60% of those killed in flood-water rescues are rescuers, he said.

Sunday’s temperature peaked at 59 degrees. It was forecast to drop to 46 degrees overnight, with a similar pattern expected today. Camarillo posted a record low temperature of 32 degrees for the date Sunday.

Snow levels in the mountains were expected to reach as low as 3,500 feet, forecasters predicted, with snow accumulating at a rate of an inch an hour. Mountain driving conditions have been hazardous because of snow combined with gusty wind. At Big Bear Lake, 15 to 23 inches of new snowfall was anticipated over Sunday and today.

A winter weather advisory was issued for motorists traveling the Grapevine section of Interstate 5 in the Tehachapi Mountains north of Santa Clarita, and forecasters expected snow to accumulate on the road overnight.

Winds reached dangerous speeds in areas including the Santa Monica Mountains, Antelope Valley and Santa Clarita Valley, said National Weather Service spokesman Bill Hoffer, with sustained winds of 35 mph or more and gusts up to 60 mph.

Fire officials say the recent Southern California wildfires have raised concerns about mudslides in parts of Santa Barbara, Ventura, Los Angeles and Orange counties.

Neighborhoods in Yorba Linda are potentially at risk because of the recent Freeway Complex fire, but officials also are concerned about areas torched in last year’s Santiago fire, including Silverado and Modjeska canyons.

“We’re really concerned about the mud and debris flows,” said Capt. Greg McKeown of the Orange County Fire Authority. “The hillsides are pretty barren at this point.”

All three fire stations in Yorba Linda -- Nos. 10, 53 and 32 -- are providing sand and sandbags around the clock. So is Station 34 in Placentia.

“Just come to the station and ring the doorbell,” McKeown said.

To help Los Angeles homeowners prepare, the Fire Department and Bureau of Street Services are distributing sand and sandbags. The empty bags, in limited quantities, are available at all city fire stations and three Los Angeles police division stations: Foothill, Mission and Devonshire.

City workers have made a special effort to provide sandbags to residents along Browns Canyon Road in the Chatsworth area and the fire-ravaged Oakridge Mobile Home Park in Sylmar.

Not all fire stations distribute sand, though. The city Fire Department website notes those that do and lists other locations with sand, including UCLA-Olive View Medical Center in Sylmar, Knollwood Country Club in Granada Hills and Hansen Dam in Lake View Terrace.

The predicted rain and snow, officials said, is good news for a state suffering from long-term drought and for winter resort operators.

Northern California ski areas, including Alpine Meadows and nearby Squaw Valley, reported up to a foot of new snow from a storm this weekend. The National Weather Service predicted a chance of an additional 1 to 2 feet of snow in the northern Sierra Nevada range through Tuesday afternoon.

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howard.blume@latimes.com

Times staff writer Garrett Therolf contributed to this report.