A brush fire in Azusa grew Monday night to 190 acres as flames chewed up pockets of unburned vegetation along the flanks of the blaze, officials said.
The U.S. Forest Service had said the blaze was holding at about 50 acres, but aerial mapping completed late Monday showed that it had grown to 190 acres, said Nathan Judy, spokesman for the Angeles National Forest.
"We're still making progress," he told The Times.
But the blaze, he added, "is going to go through the night."
The fire was 5% contained after breaking out Monday evening on the north side of California 39 in San Gabriel Canyon, the U.S. Forest Service said.
A Forest Service helicopter and another one from the Los Angeles County Fire Department were making repeated drops on the fire as crews on the ground cut containment lines and knocked down hot spots, fire officials said.
As flames came close to a housing development along California 39, voluntary evacuation orders were issued about 7 p.m. for residents on Foxtail and Poppyglen courts, the Azusa Police Department said.
The fire also forced road closures in the Duarte area, the Los Angeles County Sheriff's Department said.
Huntington Drive was closed at Encanto Parkway, and residential streets that intersect Encanto Parkway north of Huntington Drive into Fish Canyon were also closed, the department said.
The blaze, called the Madre fire, quickly spread from less than an acre as flames raced up a mountainside.
Earlier, a Super Scooper aircraft was making repeated aerial assaults on the flames. The aircraft does not operate at night, officials said.
Thick clouds of smoke could be seen for miles.