At least 150 people have been evacuated from their homes as erratic winds Wednesday fanned a wildfire burning through rugged hills in Northern California and pushed the flames across two counties.

Many in the region about 100 miles north of San Francisco had only recently returned to their homes after fleeing an earlier blaze.

Crews lit backfires Wednesday along a road elsewhere in the region as plumes of black and white smoke rose into the sky.

The California Department of Forestry and Fire Protection said the fire had expanded across 26 square miles and crews had the flames just 6 percent contained. Full containment wasn't expected until Monday.

The fire began in dry timber and brush Sunday several miles from the community of Lower Lake. It leapt from Lake County into wine-famous Napa County, but no vineyards were threatened.

Empire Mini Storage manager Desiree Mcalear said the business in Middletown has had numerous calls and visits from people who want to rent units in case they have to evacuate.

"They're absolutely scared and terrified," she said. "If the winds decide to blow this way then we all need to take action. Right now we have the luxury of waiting and being patient."

More than 1,100 firefighters were battling the blaze that was threatening 50 structures. No homes have been destroyed, and no injuries have been reported.

Meanwhile, firefighters have nearly surrounded a larger nearby blaze that started about two weeks ago and destroyed 43 homes

The causes of both fires remained under investigation.

Temperatures have been relatively mild, but the gusty winds and dry conditions have stoked the wildfires.

In Southern California, evacuation orders were lifted as crews increased containment of a small wildfire sparked by a burning motor home in rural Riverside County.

Officials say one person from the motor home was burned. Three firefighters were taken to hospitals with minor injuries.

State fire officials said the blaze about halfway between Temecula and Palm Desert had been held to 450 acres and was 50 percent contained.

Statewide, 16 active wildfires were burning and being fought by more than 11,000 firefighters.