Clean-up efforts are under way east of Los Angeles after heavy rain unleashed mudslides in a mountain area scorched by a wildfire two years ago, sending boulders across roads, carrying away cars and prompting evacuations and shelter-in-place orders.
Firefighters went street by street to make sure no residents were trapped after mud flows began inundating roads on Monday night near the community of Forest Falls.
Eric Sherwin, spokesman for San Bernardino County Fire Department, said crews had not found anyone who needed to be rescued and no one was reported missing.
Multiple homes and other structures had varying levels of damage, he added, including a commercial building where the mud was so high it collapsed the roof.
Rocks, dead trees and other debris surged down slopes with astonishing force in Forest Falls, Oak Glen and Yucaipa, he said.
“We have boulders that moved through that weigh multiple tons,” Mr Sherwin said. “It could take days just to find all the cars that are missing because they are completely covered by mud.”
Social media video from Oak Glen showed a torrent of mud racing down a hillside, across a road and into a restaurant car park.
Concerns about more thunderstorms on Tuesday prompted authorities to keep about 2,000 homes in the San Bernardino Mountains communities under evacuation orders.
For some homes in Forest Falls, it was too late to evacuate on Monday and residents were told to shelter in place through the night because it was safer than venturing out.
The rains were the remnants of a tropical storm that brought high winds and some badly needed rainfall to drought-stricken southern California last week, helping firefighters largely corral a wildfire that had been burning out of control about 20 miles south of the mudslides.
The mud flows and flash flooding occurred in parts of the San Bernardino Mountains where there are burn scars from the 2020 wildfires.
“All of that dirt turns to mud and starts slipping down the mountain,” Mr Sherwin said.
The mudslides came after a week that saw California endure a record-long heatwave. Temperatures in many parts of the state rocketed past 38C and pushed the state’s electrical grid to breaking point as air conditioners sucked up power.
The Fairview Fire in southern California and the Mosquito Fire east of Sacramento broke out and raged out of control.
The tropical storm aided crews battling the Fairview Fire about 75 miles south east of Los Angeles. The 44-square-mile blaze was 62% contained by Tuesday.
Two people died fleeing the fire, which destroyed at least 30 homes and other structures in Riverside County.
The Mosquito Fire has grown to 78 square miles, with 18% containment, according to the California Department of Forestry and Fire Protection.
While crews were able to take advantage of cooler temperatures and higher humidity to strengthen control lines, more than 5,800 structures in Placer and El Dorado counties remained under threat, and 11,000 residents were under evacuation orders.
Scientists say climate change has made the west warmer and drier over the last three decades and will continue to make weather more extreme and wildfires more frequent and destructive.
In the last five years, California has experienced the largest and most destructive fires in its history.
