At Least 1,000 Flee Wildfire In Calif.

Darkness didn't keep firefighters from continuing to gain ground Monday on a 400-acre wildfire they have been battling all weekend near Los Angeles.

It just meant a change in tactics.

"The hand crews are still making progress against the flanks of the fire," Cliff Johnson, fire information officer for the Angeles National Forest, said early Monday. "(But) no aircraft are being used in the darkness."

All of Sierra Madre's schools have canceled Monday classes, and the early season wildfire forced the evacuation of at least 1,000 people from their homes in the foothills. Authorities said no homes have burned.

On Sunday, water-dropping helicopters and air tankers went to work against the fire, which was slow-moving at first, but later shifted to the southwest and threatened homes, CBS News affiliate KCBS reports.

About 500 firefighters attacked the blaze, said city of Sierra Madre spokeswoman Elisa Weaver.

"This is pretty serious," Weaver said. "Some of these areas have not burned in over 40 years."

By Sunday evening crews had the fire 30 percent contained, Sierra Madre spokesman James Carlson said. Light winds and rising humidity were aiding firefighters, who hoped to have the blaze fully contained within a week, Carlson said.

Monday morning will see the return of firefighting aircraft and likely more ground crews, Johnson said.

On Sunday, helicopters made water drops on a steep ridge above Sierra Madre near Bailey Canyon Wilderness Park, about 15 miles northeast of Los Angeles and just east of Pasadena. A fixed-wing water tanker also dropped flame retardant.

Aircraft also were helping fire officials assess the movement of the blaze, which was had been creeping northwest into Angeles National Forest, Battalion Chief Tim Davis of the Forest Service said.

"It's very steep, inaccessible terrain, and it's very heavy brush," Davis said at a news conference. "Very difficult and arduous labor for these crews. You can't get bulldozers into the majority of where these fingers of fire run."

Two firefighters had minor injuries - one was treated for heat exhaustion, another for a strained knee, authorities said.

The blaze stranded 50 guests from a wedding party at the Chantry Flats ranger's station on Saturday until they were airlifted out Sunday afternoon, Weaver said. It took five helicopter trips from the ranger's station to the wedding's parking area. The party then was escorted out by road.

Investigators were trying to determine the cause of the fire, first reported on a windy Saturday afternoon as temperatures approached 100 degrees.