Thousands of residents have fled their homes in northern California as some 5,000 firefighters tackle wildfires.
One blaze, the Valley Fire, which started on Saturday in Lake County, north of San Francisco, has already burned 40,000 acres (16,190 hectares).
Four firefighters were injured and had to be airlifted to hospital, where they are said to be in a stable condition.
The fires across northern California are being blamed on high temperatures and years of drought.
The state spent $212m (£137m) fighting the flames in July alone, California’s forestry and fire protection department spokesman Daniel Berlant told the AFP news agency.
He said more than 275 homes and other buildings had been destroyed and the Red Cross is opening emergency shelters for evacuated residents.