More than 4000 firefighters have made progress in controlling California's largest wildfire on record, as a mechanic helping to fight a separate blaze in the state was killed in a road accident.
A man has also been arrested on suspicion of setting a third wildfire and has been charged with multiple criminal counts including aggravated arson and making criminal threats.
The Mendocino Complex Fire is the largest of 10 major fires in California and despite the latest progress by firefighters, has burned more than 123,000 hectares, CalFire said on Thursday.
Two firefighters have been injured and 119 homes destroyed by the fire.
A mechanic helping to fight the Carr Fire burning around Redding in northern California died on Thursday in a crash on a highway in nearby Tehama County, the California Department of Forestry and Fire Protection (CalFire) said.
The 71,224ha Carr Fire, 322 km north of San Francisco, has killed two other firefighters along with three members of one family and has destroyed nearly 1100 homes.
It was 48 per cent contained with firefighters struggling in steep terrain to control the blaze, CalFire said.
Winds gusting up to 56km/h and temperatures above 32C are forecast until Saturday in northern California.
Further south, 51-year-old Forrest Clark was arrested on suspicion of setting a 3885ha fire in the Cleveland National Forest area of Orange County near Los Angeles.
He was charged with multiple criminal counts including aggravated arson and making criminal threats, the Orange County District Attorney Office said on Thursday.
The man faces a maximum sentence of life in prison if convicted and is being held on bail of $US1 million ($A1.4 million).
The fire he is accused of starting has displaced 20,000 people and is only five per cent contained