The Valley Fire in Lake County has swelled exponentially to 25,000 acres hours after four firefighters were injured fighting it when it first emerged earlier Saturday, according to Cal Fire officials.
All four of the firefighters suffered second-degree burns and are in stable condition at UC Davis Medical Center, according to Daniel Berlant, spokesman for Cal Fire.
According to Cal Fire, mandatory evacuations have been ordered for High Valley Road, Bottle Rock Road, Harbor Hot Springs and Big Canyon Road.
It says the blaze is burning through oak grass woodland and threatening several structures. The cause of the blaze is being investigated.
According to the Associated Press, to the east, firefighters battled the Butte Fire about 70 miles southeast of Sacramento that exploded to more than 101 square miles in four days, turning the grassy, tree-studded Sierra Nevada foothills an eerie white.
Crews increased containment to 15 percent despite a thick layer of smoke that kept air tankers and helicopters from flying Saturday.
The fire, which broke out on Wednesday, destroyed 86 homes, 51 outbuildings and was threatening about 6,400 more.
You can see more information on this blaze and others on KPCC's FireTracker: