The county Office of Emergency Management said the blaze started as a structure fire that spread to the vegetation.
The California Department of Forestry and Fire Protection said Thursday night that the blaze had burned almost 8 square miles (20 square kilometers).
"We are still in the early stages of aggressively attacking this fire with both ground and air resources", she said.
The Klamathon Fire was one of more than three dozen wildfires that firefighters were battling in California and across the U.S. West during an unusually active fire season.
Mandatory evacuations are in place for the communities of Hornbrook, Hilt, Colestin and Irongate Reservoir.
Map showing the approximate location of the Klamathon Fire at 11:41 p.m. PDT July 5, 2018.
"We just grabbed everything you can't replace or re-buy", Stanfill said.
CAL FIRE said the evacuations came into effect in Hornbrook at 4.40 p.m. local time (7.40 p.m. EDT) and an evacuation shelter was established at Jackson Street School in Yreka.
Cal Fire's updates on evacuation advisories and road closures in the area can be found here.
No more deaths were expected. Numerous structures have burned and several hundred people have been ordered to evacuate. But the threat of a deluge raised the possibility of flooding at a stubborn blaze in the southwestern corner of the state. Officials issued a flash flood watch for the 85-square-mile area burned by a fire that started June 1. They say it is just smoldering and rain over the coming days should keep it from spreading.
The state fires are among 60 large blazes burning in 13 states, according to the National Interagency Fire Center.