An atmospheric river was set to begin pummeling much of California with heavy rain and snow 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.

An intense storm could cause flooding and debris flows in areas burned by wildfires. Some residents have begun to evacuate.

Storms dumped snow and freezing rain on a swath of the eastern U.S. stretching from Kentucky to the nation's capital.