Dozens of homes burned to the ground as a wildfire raged over ridges and tore through rural communities in central California, authorities said.

The streaking blaze that burned at least 60 homes northeast of Bakersfield around Lake Isabella came just as many others across western states were calming.

It broke out late Thursday afternoon amid heat in the 90s and single-digit humidity, climbing over at least three ridges into hillside neighborhoods, Kern County fire Capt. Tyler Townsend said.

Some houses were already little more than embers on the ground, while others were deep in flames. No injuries were reported.

"I've never been in a wildland fire where I've seen so many homes burn," Townsend said. "It's one of the most devastating I've ever seen."

The fire has burned over four square miles, and about 1,500 homes are under threat. Several thousand people were under evacuation orders.

Hillside homes along dirt roads were consumed by heavy flames in Squirrel Mountain Valley, a community of about 500 people.

Smoky haze could be seen for miles around, and orange flames lit the evening air as planes and helicopters made drops on the blaze.

Many of the houses in the area have propane tanks, adding to the danger, Townsend said.

Some residents were refusing to evacuate, Townsend said.

Elsewhere in the state, cooler weather helped crews fighting two fires that burned more than 8 square miles of chaparral and brush in the Angeles National Forest and foothill communities northeast of Los Angeles. The fires were 15 percent contained.

More than 1,300 homes in Duarte and Azusa were evacuated during the 4-day-old blaze, but around half have been allowed back.

Near the San Diego County border with Mexico, an 11-square-mile fire was 35 percent contained after burning five homes. Most evacuees were allowed to return home Thursday.

In Colorado, a forest fire near the Wyoming line threatened about 40 cabins Thursday after exploding in size to more than 8 square miles, federal fire officials said.

Shifting winds sent the fire surging Wednesday from a single square mile. Trees killed by a beetle infestation fueled the flames in and around Routt National Forest, 140 miles north of Denver and 2 miles from Wyoming.

The deadwood made it too dangerous to send in crews to battle the flames, so they were attacking the fire's perimeter, fire information officer Brian Scott said.

The weather was cooler, but firefighters were keeping an eye on the sky. There was a chance of thunderstorms that could bring dangerously erratic wind and little rain.

"Then it's anybody's guess where those flames will go," Scott said.

In eastern Arizona, firefighters managed to corral nearly half of a fire that roared through about 67 square miles of pine, juniper and brush on an Apache Indian reservation.

Crews managed to light backfires that drew a "black line" around the south end of the blaze, fire information spokeswoman Rita Baysinger said. "They're really working their hearts out, and I think we've turned a corner," she said.

Still, more than 15,000 people in Pinetop-Lakeside, Show Low and nearby mountain communities were being told to be ready to evacuate if necessary.