LOS ANGELES — Emergency crews shoveled head-high mounds of mud from parts of two important highways in the mountains and desert north of Los Angeles on Friday after thunderstorms unleashed flash flood and debris flows, stranded hundreds of vehicles and forced some motorists to take refuge on top of their cars.
Excavators scooped away mud in the darkness following the Thursday afternoon downpours and cleanup continued well into Friday, leaving thousands of drivers searching for alternatives to Interstate 5 and State Route 58.
The last of several cars were being removed from Interstate 5 in Tejon Pass, but about 200 cars and trucks were scattered about on State Route 58 near State Route 14 in the southwest corner of the Mojave Desert.
The affected section of I-5, one of the state’s major north-south arteries, carries traffic among steep mountains over a pass rising to an elevation of more than 4,100 feet between the Central Valley and metropolitan Los Angeles.
The mud in the northbound lanes of I-5 was soupier than that in the southbound lanes, making it harder to scoop out, California Department of Transportation spokeswoman Lauren Wonder said.
There were no reports of deaths or injuries from the flooding, brought on by a weather system that produced powerful afternoon thunderstorms in the mountains and deserts.
After removing the debris, a geologist will check the stability of nearby slopes before I-5 is reopened, Wonder said.
The National Weather Service said a flash flood watch would be in effect again Friday afternoon and early evening for the mountains and deserts because of the continuing threat of severe and slow-moving thunderstorms, which raises the potential for flash floods and debris flows.
Rural Lake Hughes, a tiny mountainside community in northern Los Angeles County was in the path of the storm. Robert Rocha, a 37-year-old resident, said he was driving home from work when the storm arrived.
“It was getting pretty hairy out there,” he said. “I’ve never seen it rain that hard in such a short period of time, the hail and wind — it was coming down hard,” he said. “The debris was just intense — chunks of wood and rock flowing everywhere.”
Los Angeles County Fire Department Capt. Keith Mora said the agency rescued four people and two dogs from atop one car. Many more were able to walk to safety after waiting out the flood on top of their own vehicles, he said.
“They were able to use their vehicles as a security blanket, to stand on top of and stay higher than the flood water,” Mora said.
In all, the agency reported rescuing 14 people and eight animals. Los Angeles County firefighters were expecting to go house to house Friday morning to check on any stranded occupants.
The thunderstorms were powered by a low pressure system pulling in moisture from the south. As much as 1.45 inches of rain fell in a quick span of time near where the most intense flooding occurred.
The system was expected to shift slowly eastward through Friday, National Weather Service meteorologist Joe Sirard said.
In Lake Hughes, Jennifer Stewart said she had just picked up her 17-year-old daughter from school when the storm hit. Stewart said she was among about 30 motorists who were left stranded on a local road. Everyone was calm, she said.
“It’s kind of like a tailgate party without the party,” she said. “Everyone’s just quietly sitting in their cars talking among themselves.”