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.
But 270 homes and other buildings still were threatened by the blaze, which has charred more than 12 square miles since Wednesday.
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 a few miles north of Tecate, Mexico, and about 40 miles southeast of San Diego.
Three firefighters suffered heat-related injuries and were taken to a hospital for evaluations.
“We’re expecting to have pretty significant fire activity today,” said Capt. Kendal E. Bortisser of the California Department of Forestry and Fire Protection.
Other blazes burned wide swaths across Arizona and New Mexico, where firefighters also faced blistering temperatures Monday.
In central New Mexico, a 28-square-mile fire that erupted last week and destroyed 24 homes in the Manzano Mountains south of Albuquerque was largely uncontained. But higher humidity overnight allowed crews to strengthen lines around the fire.
Farther north, a small blaze ignited in a popular recreation area, and Santa Fe National Forest officials considered some youth camps and campgrounds threatened. Both camps posted social media updates saying the facilities were fine and there was no immediate threat.
In eastern Arizona, a fire doubled to nearly 42 square miles and led officials to warn a community of 300 residents to prepare to evacuate. But the blaze on the Fort Apache Indian Reservation southwest of Show Low was not moving quickly toward the community of Cedar Creek because of sparse vegetation and shifting winds.