LAKE HUGHES, Calif. (KABC) -- A massive fire burning near Lake Hughes in the Angeles National Forest flared up Friday afternoon as a blistering heat wave descended on Southern California.
Crews had been concerned that the excessive heat would trigger more destruction. By Friday evening, the Lake Fire was 12% contained and had grown by several thousand acres, with 17,482 acres scorched.
New evacuation orders were issued shortly after the flare-up. Fire crews said the flames were burning very close to the Antelope Valley California Poppy Reserve in Lancaster.
The blaze was also moving in the direction of the California aqueduct but firefighters ramped up efforts to try and stop it from jumping to the other side into Fairmont where there are more properties.
"It's going to be triple digits out here on the fire line. That's going to be a huge factor... So we have to take care of ourselves. It's also conducive for fire weather," Jake Miller with the L.A. County Fire Department said Thursday evening.
RELATED: 'Fire tornado' captured on video as massive Lake Fire marches across Angeles National Forest
Hundreds of firefighters from the Angeles National Forest, L.A. County Fire Department and several other agencies have been battling the flames, which have consumed huge chunks of the area's rugged slopes.
The Lake Fire was first reported Wednesday afternoon near the intersection of North Lake Hughes Road and Pine Canyon Road and exploded in size, from hundreds of acres to 10,000 after a few hours. Flames raced across ridges and steep slopes.
Fire officials said flames were in some areas that had not burned since 1968.
Mandatory evacuations have been in place since Wednesday. According to L.A. County Fire Department, evacuations were ordered in the area of Lake Hughes Road west of Pine Canyon Road and north of Dry Gulch Road, east of Ridge Route Road, west of Lake Hughes Road and Fire Station 78, north of Pine Canyon and Lake Hughes Road and south of Highway 138.
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Evacuation points were set up at Highland High School at 39055 25th St. West in Palmdale and the Castaic Sports Complex at 31230 Castaic Rd.
RELATED: Lake Fire: Zones under evacuation orders as blaze scorches Angeles National Forest
Officials said 5,420 structures were threatened and at least 100 structures were affected by the evacuation orders.
Officially, fire authorities have said at least three structures were destroyed. But Eyewitness News observed the ruins of a larger number, possibly a dozen or more buildings damaged or destroyed in the area near Pine Canyon Road. An official assessment of the damage is still underway as the firefight continues.
No injuries have been reported so far.
A statewide Flex Alert calling for Californians to voluntarily turn off their lights and help conserve electricity will be in effect Friday afternoon as dangerous fire conditions are expected through the weekend.
When the fire first erupted Wednesday, it created enough force to make several "fire tornadoes" and flames created an enormous column of smoke seen dozens of miles away.
WATCH: Evacuation centers established for Lake Hughes fire in Angeles National Forest
The cause of the blaze is under investigation. An area believed to be the origin point was blocked off with red tape. It's one of several wildfires burning in the region.
The Associated Press contributed to this report.