Fire crews gain ground in high desert north of Los Angeles as hills smoulder from 2-day blaze

A Boeing Evergreen B-747 Supertanker drops fire retardant in Palmdale, Calif. on Friday, July 30, 2010. A huge wildfire in the high desert wilderness north of Los Angeles jumped an aqueduct Friday, rushing toward hundreds of houses as firefighters also tried to keep flames from damaging power lines that bring electricity to Southern California. (AP Photo/Damian Dovarganes)

PALMDALE, Calif. - A wildfire smouldered in the high desert north of Los Angeles on Saturday, spewing plumes of thick smoke that prompted air quality warnings as hundreds of firefighters worked to contain the 2-day-old blaze.

The fire has charred nearly 22 square miles (57 square kilometres) of brush in the Antelope Valley. It was 82 per cent contained Saturday evening and no structures were threatened, said Los Angeles County Fire Inspector Don Kunitomi.

Some 1,300 firefighters were assigned to the fire near Palmdale, a city of 139,000. The crews were concentrating on digging up any remaining brush along the containment lines established around the blaze, Kunitomi said.

The firefighters' primary concern was that winds could re-ignite embers smouldering throughout the blackened hillsides, Kunitomi said.

Embers apparently carried by winds across an aqueduct late Friday prompted a new flare-up that approached homes and menaced power lines that deliver electricity to Southern California.

As many as 2,300 structures were threatened at the height of the fire late Thursday. Evacuation orders were lifted Friday morning, but some roads remained closed.

One house and three mobile homes were destroyed, authorities said, and much of the region's air remained smoky.

South Coast Air Quality Management District officials warned that air quality could reach dangerous levels in portions of the Antelope Valley, San Gabriel Mountains and southern Kern County.

Deputy Fire Chief Michael Bryant said an investigation into the cause of the fire is centring on workers who were hammering on some bolts to remove a tire rim.

Crews also were working to snuff out a wildfire that has burned about 15 acres (6 hectares) of heavy brush in the Angeles National Forest above Glendora, west of Pasadena.