A fast-growing brush fire that broke out Thursday morning above Glendora started to overrun hillside homes as it grew to more than 125 acres, prompting evacuations, authorities said.
The fire, reported just before 6 a.m. near the intersection of Glendora Mountain Road and Colby Trail Motorway, was sending a huge plume of smoke into the air as it advanced south down the hillside, overtaking at least two homes and other structures, aerial news footage showed.
Mandatory evacuations were in place for areas west of Glendora Boulevard to North Sierra Madre Boulevard, according to an alert issued by the Los Angeles County Sheriff's department.
"All we're doing is going up and seeing how many people we can convince to get out of there .... We can only be as firm as we can be," sheriff's Dep. Rob Upham said.
Glendora police issued an alert "strongly" recommending evacuations for residents living between Grand and Glendora Mountain Road, north of Sierra Madre.
County firefighters were working with Forest Service crews to attack the blaze, as more water-dropping helicopters were called in.
Angeles National Forest spokesman Nathan Judy told KTLA-TV at about 7:15 a.m. that the blaze had grown.
"Our fuels are very dry, they've been that way all year," Judy said.
Miguel Orneals of the L.A. County Fire Department said his agency was requesting more equipment for structure protection because the blaze was threatening residences and homes.
As the flames advanced down the hill, authorities warned residents to prepare to leave at a moment's notice and not take any chances.
"If you feel uncomfortable, if the hairs are standing up on the back of your neck ... just go ahead and evacuate," Judy told KTLA. "Let us do our jobs and take control of this fire and then you can come back in."
The circumstances are such that if a fire were to ignite, "there could be rapid spread of wildfire," the weather service warned Thursday.