As some residents whose homes were threatened by a vast Southern California wildfire were allowed to return home on Monday, forecasters warned that the cooler, damper conditions that have aided recent firefighting efforts would soon turn in favor of the flames.

More than 2,000 residents were allowed to return to their homes in Goleta, about 85 miles northwest of Los Angeles, said Roger Aceves, the city's mayor pro tem. Five fresh crews from Arizona and New Mexico, totaling 100 firefighters, were brought in Monday to help battle the 15-square-mile blaze.

Firefighters had contained 35 percent of the fire in the Los Padres National Forest that is threatening the city, mainly on its southern side bordering neighborhoods.

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But some mandatory evacuation orders and warnings to be ready to leave remained in effect for scattered homes on the fire's growing western flank on the Santa Ynez Mountains, Aceves said.

"We know what can happen," Aceves said. "This is brush that hasn't burned since 1955."

About 36,000 customers in the Santa Barbara County lost power around 8 p.m., said Southern California Edison spokeswoman Nancy Williams. Nearly all had their power restored within an hour, she said. It was at least the sixth straight day that transmission lines have been affected by flames and smoke.

Officials responsible for the 125-square-mile blaze near Big Sur and the 40-square-mile Piute fire in the Sequoia National Forest east of Bakersfield said those blazes won't be controlled for at least another two weeks.

Mike Smith, a meteorologist with the National Weather Service in Sacramento, said that over the next couple of days, California's coastal regions would get warmer temperatures and offshore breezes that would keep moist marine air from coming inland.

Wildfires have blackened more than 800 square miles and destroyed at least 69 homes throughout California, mainly in the northern part of the state, in the past two weeks. One firefighter died of a heart attack.

Fire officials said they don't expect the fires near Big Sur or Piute to be controlled for at least another two weeks.

The Big Sur fire, which is 18 percent contained, was burning through the remote Ventana Wilderness, where difficult access has made it hard to build containment lines, said Jim Turner, spokesman for the U.S. Forest Service.

A mandatory evacuation remained in effect for all residents of Big Sur. Firefighters were struggling to widen fire lines near the Pacific Coast Highway and residential areas to between 300 feet and a quarter mile, Turner said.

Crews secured a Boy Scout camp near Big Sur on Monday by burning out brush between the buildings and the wildfire's edge and were setting controlled fires elsewhere to halt the blaze's march, the Forest Service said.

The Piute fire was 26 percent contained. Wind caused the fire to jump containment lines Monday. Air tankers and helicopters dumped flame retardant.

"The steep challenging terrain makes it tough to work directly," said Bob Kurilla, Piute fire spokesman. "It will take a little while, but we're making progress."