The Summit Fire was reported about 12:50 p.m. Friday near Jesus Canyon Road and East Avenue Z, near the Los Angeles County-San Bernardino County line, which initially burned through eight acres of brush.
The Angeles National Forest says the fire has charred 2,677 acres as of Saturday morning. Containment remained at 0%.
A map of the evacuation areas can be viewed below.
An evacuation shelter is open at Antelope Valley Family YMCA, located at 43001 10th St W in Lancaster. Small pets are allowed.
An animal shelter for small animals is available at Los Angeles County Animal Care Center located at 38550 Sierra Highway in Palmdale.
The fire ignited in a sparsely populated area near the communities of Llano and Piñon Hills off Highway 138 before spreading into the Angeles National Forest.
Fire crews prepared for an extended battle as nearly a dozen aircraft hit the flames from above. Helicopters and fixed-wing aircraft dropped water on the flames, with helicopters refilling from an aqueduct. At least one military C-130 aircraft also assisted.
"I think we saw like seven or eight helicopters, and then five or six planes. There were some really big ones. Cal Fire is out here putting in their best efforts, for sure," said Nicholas Cox of Apple Valley.
The blaze erupted during the afternoon amid hot conditions.
"Temperatures were in excess of nearly 100 degrees here. I know we had some winds about 10 to 15 miles an hour coming out of the east," said Los Angeles County Fire Department Engineer Jonathan Torres.
All children and counselors were safely evacuated from the AYF Camp south of the fire's location.
Residents watched the fire spread across mountain terrain.
"We've definitely have seen it start down low. We've seen it work its way up the mountain, and it looks like its cresting over this ridge right now, but that's the biggest concern, honestly, going back toward Wrightwood," said Drew Everett of Apple Valley.
Fire officials said the blaze was burning toward the area of the Bridge Fire burn scar near Wrightwood, where nearly 100 structures were destroyed in a previous wildfire.
The Summit Fire damaged some buildings, though many others were saved. Residents captured images and video as smoke darkened the sky.
Nearly 600 people were under a combination of evacuation orders and evacuation warnings.
Some residents, including Bud Horstmeyer of Piñon Hills, chose to remain and monitor conditions despite the fire's rapid spread.
"Just wasn't enough work on it right away, and it just kind of got out of hand, but they'll get it out. These guys are the best," Horstmeyer said.
Firefighters continued their efforts as evacuation orders and warnings remained in effect.
No injuries were immediately reported. Crews on the scene reported some outbuildings had been damaged or destroyed, and occupied structures were in the path of the flames.
The fire burned into the Angeles National Forest and was advancing toward San Bernardino County.
The South Coast Air Quality Management District issued a smoke advisory due to the fire, which will be in effect until 5 p.m. Saturday.
The Los Angeles County Department of Public Health issued a smoke advisory for portions of the county due to smoke from the Summit Fire. It will be in effect until 5 p.m. Saturday.
For additional information, visit: lacounty.gov/emergency
City News Service contributed to this report.