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 have gone into effect for burn scar areas across Southern California as heavy rainfall threatens dangerous debris flows.

Crews have rushed to clear out basins designed to catch mud, rocks and other debris from tumbling into neighborhoods as damaging rains approach.