[Update, 8:08 p.m.: The fire was 85 percent contained. as of late this afternoon. All evacuations have been lifted.]
A brushfire in the canyons and mountainsides above Monrovia has blackened about 125 acres and was 55 percent contained, a city spokeswoman said at midmorning.
An approximate time of when the the fire would be contained was not immediately known, said city spokeswoman Jennifer McClain.
"The fire is laying down," McLain added. "You don't see the flames."
A county fire spokesman said "we do have crews that will be out there throughout a day. They include eight hand crews and we have helicopters on standby," a county firefighter said. "We have a lot of resources that will be out there today. It will be a long day and they'll (firefighters) probably be working throughout the night.
Nevertheless, four neighborhoods involving about 100 homes remained evacuated, McLain said. The neighborhoods called Alta Vista, Briar Cliff, Hidden Valley and Highland were evacuated as a precaution, she said, "due to the potential for winds to come down through the mountains." About 200 homes had been evacuated earlier.
At one point, firefighters estimated that 175 acres had burned, but infrared camera assessment in the dark lowered that total to 125 acres.
The fire broke out near Hillcrest Boulevard and Madison Avenue at 11:06 a.m. Saturday, and in 45 minutes it had spread to 10 acres in heavy brush. Winds were reported to be light and not a factor, but it nearly doubled in size in the next hour.
Highly visible flames and smoke snarled traffic on the nearby Foothills (210) Freeway. Initial reports were that a gardener had accidentally sparked the blaze with a power tool while removing possible fire fuel.
The Los Angeles City Fire Department sent a strike team with five engines, 25 firefighters and a water-dropping helicopter to help the Monrovia Fire Department. Fire engines from Pasadena and other San Gabriel Valley cities were also called in under mutual aid arrangements.