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

Firefighters spray water on burning plants as flames race across the desert floor Friday in Palmdale, Calif. Fire officials said Saturday that most of the fire was contained.

The fire has charred nearly 22 square miles of brush in the Antelope Valley. It was 82 percent 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 main objective is always to get a cold trail cut around the fire line,” he said.

The firefighters’ primary concern was that winds could re-ignite embers smoldering 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.