By CBSLA Staff

ANGELES NATIONAL FOREST (CBSLA) — Firefighters Friday were continuing to battle a brush fire which broke out in heavy brush in the Angeles National Forest Thursday afternoon, prompting evacuations of the area.

The Dam Fire erupted around 2 p.m. near the 9500 block of North San Gabriel Canyon Road, north of Azusa, according to the Los Angeles County Fire Department, which was assisting Angeles National Forest fire crews.

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The Dam Fire burning north of Azusa, Calif., on July 30, 2020. (CBSLA)

Within two hours, the fire doubled in size. As of 9 a.m. Friday, the fire was at 217 acres and 40% contained, according to the U.S. Forest Service. Crews continued to battle flare-ups overnight.

USFS officials said they could see more danger Friday with temperatures expected to reach triple-digits.

“Tomorrow it’s going to be hot, it’s going to be dry, low humidities and we could see this fire kind of poke its head back up,” said Marc Peebles with USFS. “It could start to ramp up a little bit.”

The Los Angeles County Fire Department provided about 100 firefighters and two water-dropping helicopters to assist Angeles National Forest fire crews with the blaze.

“A very robust air and ground attack is holding back further spread. But tough days ahead in some of the steepest terrain in the Angeles, combined with a heatwave of 100-degrees-plus. Please give thanks to your firefighters,” said Angeles National Forest Fire Chief Robert Garcia.

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Mandatory evacuations were ordered north of Morris Dam to Crystal Lake.

“This evacuation is not in a developed residential area but it’s in some of the recreation areas in the forest,” Peebles said. “Essentially the evacuation area is on Highway 39, north here of Old San Gabriel Canyon Road.”

“The Crystal Lake recreation area has been evacuated, the West Fork and East Fork recreation area has been evacuated, and it’s mainly visitors recreating in the forest. There’s some … special use cabins up there, as well at the Coldbrook Campground and the San Gabriel off-highway vehicle staging area.”

Authorities were evacuating campers in the West Fork area of Angeles National Forest.

No structures were immediately threatened, though Highway 39 was closed north of Glendora. Highway 39 was expected to remain closed through at least Sunday.

VIVA Rescue, a nonprofit organization specializing in rescuing horses, offered in a Twitter post to help evacuate animals — “equines, livestock and domestic pets” — from the forest. Anyone needing its help was encouraged to send a text to 310-808-5943.

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(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)