BIG BEAR, Calif. (KABC) -- As the wildfire near Big Bear continues on its second day, its burn area has increased amid hot and dry conditions on Tuesday.
The blaze in the Holcomb Valley area charred 1,200 acres and remained 10 percent contained Tuesday. Though the acreage has increased, the flames appeared to die down overnight.
But firefighters said a sudden boom in the fire prompted mandatory evacuations for homes located on the northeast portion of Holcomb Valley Road and Highway 18. Those were specifically for the first, second and third streets along Highway 18 in Baldwin Lake.
The fire continues to move in a northeast direction, according to the Big Bear Fire Department.
The blaze also caused rolling blackouts in Big Bear and power was estimated to be fully restored within one to two days, according to the sheriff's department.
WATCH: Heat raises wildfire concerns, causes power outage
There were also voluntary evacuations in place for homes around the Big Bear transfer station, also known as "the dump," and Baldwin Lake, San Bernardino County sheriff's officials said.
Road closures:
Highway 18 between Delta Avenue north to the Mitsubishi Plant Road
Van Duesen Canyon road
Holcomb Valley Road East at Highway 18
3N69 at Hwy 18
Hiking trails and campground closures:
Pacific Crest Trail (PCT) at Highway 18 to Van Dusen Road
Doble Trail Campground
Tanglewood Group Campground
The South Coast Air Quality Management District issued a smoke advisory for portions of the eastern San Bernardino Mountains.
The blaze broke out around 3 p.m. Monday as a 10-acre fire before growing at a rapid pace. The cause of the fire was unknown.
Tuesday was shaping up to be the hottest day of the week, and the intense heat was a source of concern for firefighters.
Not only does the heat take a physical toll on the firefighters wearing heavy gear in the front lines, the heat also impacts the firefight from the air. The hotter it gets and the higher the aircraft fly, the less payload they can carry. That means they can't carry as much fuel, and they can't carry as much fire retardant. The helicopters were impacted even more than the air tankers.
Officials with the Forest Service said it's not hot enough to ground aircraft, but the scorching temps were a concern.
In Mead Valley, SoCal Edison crews attempted to restore power to 900 homes as temperatures hit 104 degrees.
The heat wave prompted California Independent System Operator to issue the first Flex Alert of 2017 in an effort to conserve electricity and lessen demand on the system.
The alert was issued for 2 p.m. to 9 p.m. Tuesday and Wednesday.