Thunderstorms and lighting strikes are threatening to worsen an already stubborn wildfire that has grown to cover about 8,500 acres in a rugged area of Mendocino County, officials said.
Nearly 60 homes have been evacuated in the area about 160 miles north of San Francisco as firefighters continue to battle the fast-moving fire.
"The concern is this weather could cause more fires and create erratic and dangerous winds for firefighters," said Lynne Tolmachoff, a spokeswoman with the California Department of Forestry and Fire Protection.
As of Sunday afternoon, the blaze remained 30% contained.
About 2,000 firefighters were fighting the blaze in steep, difficult terrain. Eleven had been injured as of Sunday. Eight of the injured firefighters were released after being treated overnight. The other three did not require hospital visits.
The fire began July 31 and was caused by lighting. It is one about 10 fires currently blazing in northern California.