An atmospheric river was set to begin pummeling Southern California with heavy rain on Thursday, prompting evacuations and school closures as officials warned about life-threatening flooding and mudslides in areas charred by the wildfires that broke out across the region last month.

Evacuation orders and warnings are going into effect Thursday morning for the Los Angeles area burn zones as the strongest winter storm of the season drenches Southern California. Residents in the Palisades and Eaton fire burn zones have been preparing for several days to keep their homes safe from potential mud and debris flows in