As of midafternoon, rain had picked up in some areas, and Caltrans crews were working at many locations to clear debris from roads and reduce flooding.

For the second time this year, Southern Californians are evacuating their homes as heavy rain threatens new destruction in places still recovering from last month’s devastating wildfires.

An atmospheric river is expected to bring torrential rain to California this week, threatening parts of the state with flash floods and mudslides.