Crews worked through the night to fight a wildfire that has blackened nearly 100 square miles and chased scores of people from their homes in the northern Sierra Nevada.

The fire in the Plumas National Forest was just 15 percent contained late Sunday and had destroyed an unoccupied summer home, a trailer and a shed since it began early last week.

A few people were evacuated late Sunday in the small town of Frank's Valley, on the fire's southeast flank, said Ron DeHart, a U.S. Forest Service spokesman.

Mandatory evacuations remained in effect for 50 to 100 people in the North Arm of Indian Valley and other small communities. Residents of Genesee and Taylorsville were urged but not required to leave their homes as changing wind turned the fire back in their direction, officials said.

Sunday's shifting wind carried smoke back to the south and southwest toward the San Joaquin Valley and San Francisco Bay area, nearly 200 miles away, authorities said. Last week, smoke from the blaze had prompted haze and health warnings in cities hundreds of miles away.

The fire had burned through 62,000 acres, or 97 square miles, the Forest Service reported.

More than 2,700 firefighters battled the flames Sunday and eight air tankers and 15 helicopters were used to drop water and fire retardant chemicals. There was no estimate when the fire might be contained, DeHart said.