Firefighters battling a huge Southern California wildfire have ordered new evacuations in a neighbourhood overlooking canyons where flames are surging.

Calming winds have helped firefighters battle a 4,000-acre wildfire that prompted a voluntary evacuation of about 200 ridge-top homes.

Chris Nguyen, Los Angeles

A huge mudslide crashed down on homes in a coastal hamlet with terrifying force, killing at least two people with 12 missing, as a Pacific storm hammered Southern California for a fourth day.