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.

Footage shot on Thursday shows the devastation caused by an atmospheric river drenching Southern California, particularly in communities burned by the Eaton and Palisades wildfires just weeks ago.

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.

A Los Angeles City firefighter was hospitalized after his SUV was swept into the Pacific Ocean during a mudslide in Malibu.

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

A Pineapple Express forms when the jet stream dips south into the tropical Pacific near Hawaii, scooping up warm, moist air and carrying it northeast across the ocean. Named for Hawaii's famous fruit and the storm's origins near the islands, these powerful systems can dump the equivalent of 10 to 15 inches of rain over two to three days.