Officials said about 700 firefighters were battling to control the blaze in an area called the Cajon Pass, the latest in a series of wildfires that have blackened nearly 300,000 acres (121,400 hectares) of the drought-parched U.S. West.
“It is a very fast-moving fire, it has wind behind it,” said U.S. Forest Service spokeswoman Lyn Sieliet.
Two firefighters were trapped by flames in the effort to evacuate residents and defend homes, but managed to escape with only minor injuries, fire officials said.
The so-called Bluecut Fire erupted in heavy brush just west of Interstate 15, the main freeway between Las Vegas and the Los Angeles area, forcing the closure of one stretch of the highway.
The inferno prompted orders for residents of the community of Wrightwood, about 75 miles (120 km) east of Los Angeles, to leave their homes, said Lynne Tolmachoff, of the California Department of Forestry and Fire Protection.
In all, about 82,000 people were ordered to flee, as flames destroyed an unknown number of houses, the Cal Fire spokeswoman said by telephone.
The fire remained unchecked, having exploded within hours to cover an area of 15,000 acres (6,070 hectares), Cal Fire said, up from an estimate of 9,000 acres (3,640 hectares) on Tuesday evening.
The Bluecut Fire, whose cause officials said they were still investigating, came as crews more than 600 miles (970 km) to the northwest began to make headway against a Northern California wildfire that has destroyed more than 175 homes and businesses.
The so-called Clayton Fire was 35 percent contained, according to Cal Fire. It has charred 4,000 acres (1,620 hectares) in and around the community of Lower Lake, forcing hundreds of people to flee.