LOS ANGELES — City inspectors worked Tuesday to determine what caused the second landslide in the Hollywood Hills since an early January collapse during California's siege of heavy winter rains.
The landslide Monday evening caused part of a backyard and hillside to plunge into a street in front of homes below.
Three homes were red-tagged and another was yellow-tagged but the full extent of damage and the root cause were still being assessed, said Dave Lara, spokesman for the Los Angeles Department of Building and Safety.
No one was injured but firefighters had to help residents out of one home.
There were also no injuries in the similar Jan. 11 slide that dropped a pile of earth and debris on a road below a hillside house.
Both slides occurred in the Laurel Canyon area, where many homes are clustered atop or below steep slopes amid winding roads, but unlike the first slide the most recent one occurred under clear skies more than a week after the last of the rains cleared out.
Experts say, however, that the risk of landslides can persist long after stormy weather ends as rainfall slowly percolates down through soils and bedrock, destabilizing slopes.
Los Angeles has had more than 14 inches of rain, more than double the average to date and close to the average of an entire rainy season, with February and March still to go.
Each round of rain has raised concerns about potentially destructive muddy runoff flowing off the thousands of acres around the region that have been denuded by wildfires.
But there are significant examples of rainfall taking its time to unleash devastating earth movements.
One of Southern California's most famous slides hit the Bluebird Canyon area of Laguna Beach on June 1, 2005, destroying or damaging a neighborhood of expensive homes and costly public infrastructure.
No rain fell during or immediately beforehand, but the U.S. Geological Survey said that slide was almost certainly linked to extremely heavy rains that occurred from December through February of the previous winter.
"As ground water rises, slopes can become unstable and begin to move, even if no rain is presently occurring," the USGS said at the time.
Experts say that during dry periods, residents of Southern California foothill and mountain areas should keep an eye out for signs of cracks or fissures appearing in soils or telltale indicators like tilting utility poles.