Officials urged motorists to slow down as fog descended on Southern California roadways early Monday.
The National Weather Service said a patchy dense fog was expected to affect portions of Los Angeles, including the San Fernando Valley, before 10 a.m. on Christmas Eve.
"Motorists should slow down and use low beam headlights if encountering dense fog," NWS Los Angeles tweeted.
In West Covina, where a fatal wrong-way crash had just occurred, California Highway Patrol Sgt. Karie Mendoza also asked drivers to take precautions.
"Drive slowly please… It’s very hard to see out here, so be careful," Mendoza said.