Rain accompanied by strong winds will douse the Southland today, raising the risk of flash flooding in much of the region and mud slides in neighborhoods below hillsides denuded by wildfires, National Weather Service forecasters said.
A flash flood watch will go into effect at 8 a.m. today and remain in force through late tonight over a wide area that includes beach cities, metropolitan Los Angeles, the Hollywood Hills, L.A County Mountains, Santa Catalina Island, and the San Fernando, Santa Clarita, San Gabriel and Antelope valleys, as well as areas in Ventura and Santa Barbara counties. In Orange County, the watch will take effect at 9 a.m.
The rain, along with gusty winds, is the result of a Pacific storm system. Forecasters said the storm should drop about 1 to 2 inches of rain along the coast and in valley areas, and 2 to 5 inches in the mountains and foothills.
Rainfall rates of around a half-inch per hour are expected “possibly for several hours, which could produce dangerous flash flooding, with damaging mud and debris flows,” according to an NWS statement.
“While all recent burn areas will be threatened, areas especially at risk include the Springs, Colby, Powerhouse and Williams burn areas.”
A wind advisory will be in effect in the San Gabriel mountains in Los Angeles and Ventura counties from 2 p.m. today until 3 a.m. Wednesday.
Southeast-to-south winds of 25 to 35 miles per hour with 50-mph gusts are expected in the mountains, mainly above 5,000 feet, an NWS statement said.
The wind could prove to be a problem for motorists on Interstate 5 in the area of The Grapevine, and on Angeles Crest Highway, especially for the drivers of high-profile vehicles and vehicles towing trailers, according to an NWS statement.
City officials in Glendora have been warning residents near the Colby Fire burn area to prepare for possible mudslides and debris flows. The alert issued by the city requires residents to remove vehicles, trash bins and other obstructions from the street to ensure emergency crews can access the area — and to prevent any damage from mudflows.
The Glendora alert level, which has been at yellow, will be raised to orange at 6 a.m., urging residents to voluntarily evacuate areas endangered by flooding and debris. An evacuation center will be set up at the Crowther Teen & Family Center, 241 W. Dawson Ave. The Inland Valley Humane Society will be available at the center to offer assistance with pets. Horses can be taken to the Pomona Fairplex, 1101 W. McKinley Ave.
The affected burn area is generally described as the area north of Sierra Madre Avenue between the western city limits to the eastern boundary of properties on the west side of the Little Dalton Wash.
In the fire-scarred areas of Silverado Canyon in Orange County, residents were also preparing for possible mud flows. Emergency officials issued a warning to residents and even suggested voluntary evacuations beginning at 7 a.m. today. They said Silverado Canyon Road could potentially be closed.
Residents in the 40 to 50 homes from 30311 Silverado Canyon Road to the end of the canyon were advised even before today’s rains began in earnest to evacuate, Orange County sheriff’s Lt. Jeff Hallock said.
Some cities, including Fullerton, Mission Viejo and Costa Mesa, are providing residents with free sandbags to help them protect their properties.
Sand and sandbags were also made available at Los Angeles Fire Department stations. Burbank officials are offering residents sandbags at the Public Works Field Services Yard at 124 S. Lake St.
In Long Beach, city crews were working to clear catch-basins, test pump stations and fortify sand berms on beaches. The city also installed booms to prevent debris from flowing into marina areas, and deployed additional staff such as swift-water rescue teams to quickly respond to emergency situations.
Showers are expected to continue into Tuesday night and into Wednesday, according to the NWS. The area is expected to slowly dry out as the week wears on.
The Los Angeles County Department of Public Health warned beach goers to avoid storm discharge areas due to debris and bacteria.