A wind-whipped wildfire near Lake Berryessa has consumed more than 6 square miles and prompted authorities to order mandatory evacuations of Quail Ridge and Golden Bear.
Cal Fire says it brought in six air tankers, 16 truck companies, 11 bulldozers and five water tenders to try to slow down the blaze, now being called the Wragg Fire.
It broke out shortly before 2:30 p.m. on Wednesday.
Officials say the cause of the fire is under investigation. They initially said the fire apparently started when a car caught on fire on Highway 121.
Cal Fire says nearly 400 firefighters are fighting the blaze. But they are having difficulty gaining access to the fire, which was burning through brush-covered rugged terrain.
This fire is only 5 percent contained.
Campers at Canyon Creek Campground and hikers in the Cold Canyon area of Napa County were evacuated.
No structures have been damaged and no injuries have been reported.
