A wildfire in the heavily populated Los Angeles foothills threatened 10,000 homes on Sunday, and California Governor Arnold Schwarzenegger warned residents to heed evacuation orders for the out of control and very dangerous blaze.

The heat-driven fire nearly doubled in size overnight and has now burned 35,000 acres of thick, bone-dry brush in the mountains above five towns, a 12-mile stretch from La Crescenta to La Canada Flintridge, the California Fire Department said.

Authorities have ordered residents to evacuate about 2,000 homes threatened by the fire about 15 miles northeast of downtown Los Angeles.

These fires are still totally out of control, Schwarzenegger told reporters at the firefighters' command post in Lake View Terrace, California. This is a huge and is a very dangerous fire. The fire is moving very close to homes and to structures... this is why it's important to pay close attention to the evacuation.

In La Crescenta, the streets were deserted on Sunday afternoon except for a few residents fleeing with their suitcases and other belongings on foot.

Bob Sebesta, 47, sat watching the burning ridge from his in-laws' house, which everyone evacuated last night with pictures, paperwork and stuff you can't replace.

I keep thinking I should go water the backyard, Sebesta said.

Three remote homes have been destroyed so far and some 10,000 others and 2,500 other buildings are in danger, as is Mount Wilson, the nexus for key telecommunications facilities.

That site is the nerve center for most of communication in the Los Angeles area, Station Fire Commander Mike Dietrich said. It is not out of danger as we speak.

Fire commanders said at a news briefing that more than three homes were lost in the Big Tujunga canyon, though they did not know the exact number.

We have eyewitness reports that our house is gone and as many as 30 may be lost, said Beth Halaas, who lives year-round in the canyon, where most homes are for weekend use.

The fire that started on Wednesday above the exclusive community of La Canada Flintridge is only 5 percent contained and officials expected that, with hot temperatures and low humidity, it would grow larger. The cause of the fire is being investigated.

HEALTH WARNINGS

Dense smoke filled the skies over the foothills and authorities issued health warnings for the Los Angeles basin.

The flames appeared to wane on Saturday evening in the area near NASA's Jet Propulsion Laboratory but raged at the other end and moved through the mountains toward the inland community of Acton, where evacuations were ordered on Sunday.

A wooded neighborhood on the slopes of La Crescenta got the evacuation order in the middle of the night, but only around half the neighborhood left.

On Sunday afternoon, brothers Vince and John Bollier looked out onto the mountains in front of their parents' house, where the fire had left only gray ash on the slopes.

Last night was an inferno, said Vince Bollier. It was close but it wasn't life threatening, although a lot of people would have characterized it as dangerous.

Sheriff's deputies spent Sunday afternoon urging residents to leave, and it appeared that most had.

Helicopters have been flying over the neighborhood for days now, filling up with water to drop along the area where homes meet the bone dry wilderness.

The saving grace in the Station fire has been the absence of high winds, but much of the brush in the area has not burned in 60 years, terrain is difficult to access and humidity is low. Winds were picking up on Sunday afternoon.

Four firefighters have been injured and three civilians have suffered burns, including two who were badly burned on Saturday after they tried to ride out the fire by sitting in a hot tub.

More than 2,000 firefighters and other personnel are on the ground but it is the aerial assault with water and retardant that has best kept the fire from moving into homes, many of them worth millions of dollars.

The relative lack of high winds has made fighting the fires from the air difficult because thick smoke hanging over them made them hard to see, Schwarzenegger said, adding that many of the flames are up to 80 to 100 feet high.

Utility Southern California Edison said the blaze has cut power to about 250 customers.

The mayor of La Canada Flintridge, Laura Olhasso, said the situation was looking better for residents after firefighters beat back flames from backyards overnight, and evacuation orders were lifted for some residents on Sunday afternoon.

Schwarzenegger declared a state of emergency in Los Angeles County last week in response to four fires in the area.

On Sunday, he said, there were eight huge fires burning statewide. In total, 55,000 acres have burned, he said.

(Additional reporting by Nichola Groom in Los Angeles; editing by Mohammad Zargham)

California