The National Weather Service has issued a Dense Fog Advisory for the Mother Lode through 9 AM Sunday.
Fog is affecting several locations of the Mother Lode including Highway 49 between Sonora and Jackson.
Visibility is less than a quarter of a mile.
Fog is also affecting the central valley including Oakdale, Eugene and Highway 99 between Stockton and Turlock.
When encountering fog, slow down, use your low-beam headlights and leave plenty of distance ahead of you.