Incoming heavy rain from an atmospheric river-fueled storm that slammed into the West Coast early Wednesday is threatening mudslides and debris flows in Southern California and has already prompted evacuations in the Los Angeles area.

California braced for the arrival of a major Pacific storm on Wednesday, enacting road closures and issuing evacuation warnings in parts of Los Angeles and Malibu vulnerable to mudslides and debris flows.

Southern California welcomed a surge of moisture that forecasters say could be the first in a series of early March storms, including a potential atmospheric river.