LOS ANGELES — New wildfires erupted Monday in Southern California and chased people from their homes as an intensifying heat wave stretching from the West Coast to New Mexico blistered the region.

Towering columns of smoke rose from the San Gabriel Mountains behind Los Angeles as the fires several miles apart devoured hundreds of acres of brush on steep slopes above foothill suburbs. Police in the city of Azusa ordered hundreds of homes evacuated.

Helicopters sucked water out of a reservoir to drop on flames while air tankers bombarded the flanks of the fire with retardant.

Officials had warned of extreme fire danger in the region as the heat wave peaked. Temperatures surpassed 100 degrees across much of Southern California well before noon, while some desert cities sizzled in the 120s.

Elsewhere, crews made progress against a nearly week-old blaze in rugged coastal mountains west of Santa Barbara, where overnight winds had pushed flames into previously burned areas, allowing firefighters to boost containment to more than 50 percent.

Another wildfire was growing near a small desert town close to the Mexico border. It surged to nearly 3 square miles amid triple-digit temperatures and forced the evacuation of about 75 people from Potrero, a ranching community about 40 miles southeast of San Diego.