Even as the calmer, less windy weather gave firefighters a break overnight with the Dixie fire, the third largest fire in California's history, the Pulmas County Sheriff's Office released the somber news.

"We have received reports of eight unaccounted for individuals," the sheriff's office said in a statement, asking for the public's help in finding them.

Five of the missing belong to the old mining town of Greenville where blazes leveled most of its downtown, about 160 miles north of Sacramento.

Greenville, with a population 800, was founded more than 150 years ago when nearby gold mines attracted settlers and merchants to the picturesque town in the Indian Valley.

Most of its downtown was left in ashes. More than 184 structures were destroyed in the town and across the area.

Nearly 447,000 acres have already burned in the Dixie fire and it was 21 percent contained by midafternoon, said Edwin Zuniga, a firefighter and spokesman for Cal Fire, the combined firefighting agencies battling the blaze.

"We're hoping to gain ground," Zuniga said. "There are favorable weather conditions, with less wind and a blanket of smoke that blocks direct sunlight. It allows a higher humidity which helps us."

Earlier in the week the fire was reported as 35 percent contained, but better mapping clarified the area, officials said.

The cause of the fire is listed as unknown but remains under investigation.