Flooding, mudslides and debris flows caused by the heaviest rain in Los Angeles and southern California in a year shut Pacific Coast Highway from approximately Santa Monica to the Malibu Pier.

On Friday, the storied coastal road had dissolved into a river of mud and debris after a powerful rainstorm sent those burned hillsides careening toward the ocean, turning canyons into rivers of mud and rocks.

A portion of Pacific Coast Highway between Malibu and Pacific Palisades remains closed Friday morning after a series of mudslides covered the road during Thursday's powerful storm. This video aired on the KTLA 5 Morning News on Feb.

In the Los Angeles area, the burn scars that carry the highest risk are those from the Eaton and Palisades fires from January and the Bridge Fire from the fall.

More than 100 homes were under mandatory evacuation orders in the city of Los Angeles, Jim McDonnell, the Los Angeles police chief, said Thursday morning. The Palisades fire destroyed thousands of homes in the city’s Pacific Palisades neighborhood last month, and hillsides remain vulnerable in the area.

Los Angeles locals are being warned of flash flooding and landslides as an incoming "atmospheric river" threatens areas hit by last month's devastating wildfires.

The biggest storm of the winter walloped Southern California on Thursday, but by Friday morning conditions were improving as the storm subsided.

As heavy rain from a large storm subsided, officials in Southern California said rock and mudslides remain a threat.