A powerful storm moved through the Los Angeles region Thursday, flooding streets, prompting evacuation warnings, and threatening mudslides in fire-ravaged areas. By Thursday evening, a debris flow had closed Mulholland Drive,

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.

A new atmospheric river is slamming California, including fire-ravaged Los Angeles, where residents are bracing for the possibility of mudslides and landslides.