LOS ANGELES -- A moisture-rich atmospheric river began dumping rain across Southern California early Wednesday, flooding roads, spinning out cars on freeways and slowing traffic to a crawl across much of the region.
The storm, fed by a plume of subtropical water vapor at the lower and middle levels of the atmosphere, had already poured up to a quarter of an inch of precipitation across the Southland early Wednesday. Rainfall rates are expected to pick up slightly through the morning commute before tapering off by the afternoon, said Andrew Rorke, a senior forecaster with the National Weather Service in Oxnard.
"Rainfall rates have honestly been a little less than we were expecting, which is a good thing," Rorke said. "It's been just enough to make the roads bad."
Shortly after 4 a.m., a semi truck skidded off the road heading from the northbound 710 Freeway to the 60 Freeway and dangled precariously off the transition bridge, forcing the California Highway Patrol to close the ramp. By 5 a.m., dozens of crashes had been reported across the region amid steady rainfall, snarling traffic along most major freeways in Los Angeles County.
The latest storm comes on the heels of the wettest November in years in parts of L.A. County.
The steady rain prompted the weather service to issue flash flood watches through noon for burn areas across Santa Barbara and Ventura counties, including the Cave, Maria and Easy fire burn scars. A flash flood watch also is in effect for the Saddleridge, Tick and Getty burn areas in Los Angeles County and portions of Orange, San Bernardino, Riverside and San Diego counties through 3 p.m.
Rainfall totals of 1 to 2 inches are expected for much of the region, but the San Gabriel Mountains could see up to 3 inches of precipitation. Peak rainfall rates are expected to range from 0.5 to nearly an inch per hour across Los Angeles County. There's also a chance of thunderstorms, which could bring even higher rainfall rates.
The weather service warns that heavy rain could cause mud and debris flows in recently burned areas, which may result in road closures and property damage.
"That's the big worry now," Rorke said. "Hopefully if one forms, it won't go over a burn area."
Heavy rain in the Bay Area on Tuesday night caused a landslide that eroded about 30 feet of hillside in San Bruno. No property damage or injuries were reported. However, the situation prompted the San Bruno city manager to declare a local emergency. Rain is expected to linger across large swaths of Northern California throughout Wednesday.
A winter weather advisory is also in effect for the Sierra Nevada through Wednesday night, with warnings of slippery roads, reduced visibility and travel delays. Between 3 and 7 inches of snow is expected to fall at elevations above 6,000 feet.
(c)2019 Los Angeles Times
Visit the Los Angeles Times at www.latimes.com
Distributed by Tribune Content Agency, LLC.