MOORPARK, Calif. (AP) — A new wildfire erupted in Southern California on Tuesday as windy, dry and hot weather turned the region into a tinder box.

The blaze erupted at midmorning northwest of Los Angeles in rural hills of Ventura County between the cities of Moorpark and Fillmore. The size of the blaze could not be immediately determined as smoke whipped across the area of scattered ranches and agricultural fields. One small building was seen ablaze.

“We’re fighting fire,” said county fire Capt. Bill Nash. “It is being driven by the winds so we’re working real hard to get ahead of it.”

More than 150 firefighters were dispatched and eight air tankers and four helitankers were ordered.

Flames were whipped by the region’s notorious Santa Ana winds, which blow from the northeast, speeding up and warming as they descend through mountain passes and canyons and push seaward. The air is extremely dry, lowering humidity levels and making brush easier to burn.

Gusts of 30 mph to 40 mph were reported in Southern California’s mountains, the National Weather Service said.

The Santa Anas also whipped up clouds of ash north and east of Los Angeles in the vast area of the San Gabriel Mountains burned over by a gigantic wildfire that continues to smolder a month after it began.

The winds caused some increased fire activity on ridgetops in the San Gabriels, but the haze was from blowing ash, not smoke columns, said Carol Underhills, a public information officer for the U.S. Forest Service.

The fire burned across 160,557 acres — 251 square miles — of Angeles National Forest after it was ignited by arson on Aug. 26. At its peak it destroyed 89 homes and caused two firefighter deaths.

The blaze chewed through heavy growth in areas that hadn’t burned in decades, leaving a carpet of ash in about a quarter of the 1,000-square-mile forest north and east of Los Angeles.

The fire remained 94 percent surrounded Tuesday, and fire commanders again pushed back the projected date for full containment, this time from Tuesday evening to Thursday morning, due to the weather.

Most of the remaining fire activity in the Angeles forest has been on the north side of Mount Wilson, the antenna-studded peak towering over suburban Pasadena and Sierra Madre, and in the Twin Peaks area on the east side of the fire, Underhills said.

The weather service also issued “red flag” warnings of fire weather conditions in other parts of California due to a combination of low humidity, high temperatures and wind.

Those areas included the hills east of San Francisco Bay and mountains to the north, the northern Sierra and northern Sacramento Valley and a large swath of the state farther north.