LOS ANGELES — Another menacing storm front moved into Southern California early Thursday morning, bringing heavy rain, flash flood concerns, strong winds and dangerous surf as the region is still reeling from a moisture-rich atmospheric river that has pounded the entire state in recent days.
The cold front and heaviest rainfall moved through the Los Angeles area around midnight, dropping about 1 to 2 inches of rain at lower elevations and 2 to 5 inches of rain at higher elevations, meteorologists with the National Weather Service in Oxnard said.
Though the storm system passed hours earlier than expected, the region remained at risk of isolated thunderstorms, strong winds and flooding through Thursday because of a cold air mass that has moved into the area in the storm's wake, forecasters said. At least 1 to 2 inches of additional rainfall were expected.
A flash flood watch remained in effect across southwestern California, and a winter storm warning was issued for the mountains of Los Angeles and Ventura counties through 10 p.m Thursday, with up to a foot of new snow expected for some of the highest regions, and gusts of wind reaching 55 mph.
High surf warnings are also in effect for much of the central and southwestern coasts through Friday, with waves potentially reaching up to 22 feet in some areas. Meteorologists expect significant beach erosion, particularly at high tide. Los Angeles County is offering sandbag pickup at a number of locations.
"Here in Southern California, it is certainly one of our strongest systems," Ariel Cohen, a meteorologist with the National Weather Service, said.
The Fish and Bobcat fires burn scar areas near Duarte, and the Route fire burn scar areas near Castaic Lake, could see up to half an inch of rain and face mud and debris flow, forecasters said. The Lake fire burn scar around Lake Hughes, north of the Santa Clarita Valley, was also of concern.
The concern for mud slides and debris flow led Los Angeles County officials to warn residents near the Lake fire burn scar and north end of the Bobcat fire burn scar in and around the Angeles National Forest to "be ready" for possible evacuations through Friday morning.
The Sepulveda Basin was shut down early Thursday due to high water levels, and multiple streets were flooded in Los Angeles, according to the Los Angeles Police Department.
"Accidents and traffic collision are everywhere" around Los Angeles, said Officer Moises Marroquin, of the California Highway Patrol said. He said roadway flooding was pervasive.
The Los Angeles County Sheriff's Department Lost Hills Station said in a tweet that downed trees and small rock slides were documented across the area and advised residents to stay home. Beverly Hills also had reports of large collapsed trees.
The Long Beach Post reported that flooding also shut down the 710 Freeway in both directions in North Long Beach, where authorities estimate water levels near Artesia Boulevard are about 3 feet high.
In the less than 48 hours since the warm front moved in, downtown Los Angeles received about 0.67 inches of rain, while Beverly Hills came in at 1.8 inches. About 2.96 inches of rain fell on Woodland Hills in the San Fernando Valley, and Newhall in the Santa Clarita Valley recorded about 1.69 inches. Rainfall totals at higher elevations exceeded 3.5 inches in some areas, including the Lechuza fire station in the Santa Monica Mountains.
Eagle Rock Reservoir recorded 1.11 inches, and Pasadena reached just 1 inch.
"These totals can go up, and probably will go up," Kristan Lund, a meteorologist with the National Weather Service said.
Thursday's storm comes on the heels of a series of storms — what experts describe as an atmospheric river — that has lashed California, prompting Gov. Gavin Newsom to proclaim a statewide emergency Wednesday to "support response and recovery efforts" across the already-saturated state.
In Northern California, where the storm has been most severe, pounding rain and strong winds Wednesday left a small child dead, triggered evacuations and power outages, and heightened fears of widespread flooding and debris flows.
Though still significant in Southern California, the worst conditions have spared the region.
"The center of the large weather system that's affecting the state is going to remain north of the region," Cohen said. "We're more on ... the southern periphery of the system. But it's still an area where the atmospheric river is going to combine with that weather disturbance to support the potential for flooding."
Elsewhere in Southern California, officials in Santa Barbara County on Wednesday ordered the evacuation of specified properties in and around areas previously scorched by the Thomas, Cave and Alisal fires, citing the risk of flooding and debris flows.
Caltrans District 5, which includes Santa Barbara County, reported a full closure of Highway 154 from the junction of Highway 154 and Highway 256 to the Junction of Highway 154 and Highway 192 because of multiple rock and mudslides, the agency said in a Tweet Thursday morning.
In Orange County, flooding closed down Pacific Coast Highway between Warner Avenue and Seapoint Street, CalTrans District 12, which oversees Orange County, said in a tweet. Meterologists received reports of downed trees in Burbank and warned of some coastal flooding and erosion at the coast.
The storm also hit parts of San Luis Obispo County, where nearly 3,000 residents were without power early Thursday morning, according to PowerOutage.Us.
Forecasters warn there's more to come.
"We have a parade of storm systems headed into the area over the next week," Cohen said.
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(Times staff writer Grace Toohey contributed to this report.)
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