The blaze, called Mill Fire, began Friday about 370 miles north of Sacramento. By Saturday morning, it was about 20 percent contained, according to the California Department of Forests and Fire Protection.
A hundred houses and buildings were destroyed by the fire, according to the authorities.
California Governor Gavin Newsom has declared a state of emergency for Siskiyou County. The emergency declaration will help residents access federal assistance and unlock state resources.
Mr Newsom’s office said the fire injured civilians and caused power cuts, destroyed homes and forced thousands of residents to evacuate. Local officials said people should plan “at least several days” to stay away from evacuated areas.
Siskiyou County, where Klamath National Forest is located, has a population of about 44,000, according to the United States Census Bureau.
Kim Greene, mayor of the small town of Weed in Siskiyou County, told the Los Angeles Times that the fire started in a sawmill.
Videos posted to Twitter by local media and journalists showed the fire destroying a Weed industrial building, burning forest land and spreading through residential areas.
Another fire, called Mountain Fire, spread simultaneously Gazelle, located 16 km northwest of Weed. Saturday morning, this fire was contained only 5% and had burned approximately 1,375 hectares of land.
More than two decades of drought and rising temperatures, exacerbated by climate change, have made California more vulnerable than ever to wildfires. The two most devastating years on record were in 2020 and 2021, based on the number of acres burned.