A blaze in rugged central Arizona had grown to 152,000 acres Wednesday and concern shifted to a pair of communities surrounded by pine forest that could be threatened.

The fire in rugged canyons north of Phoenix grew by more than 10,000 acres overnight and was expected to continue spreading through grass and desert brush. The lightning-sparked blaze was about 20 percent contained early Wednesday, down from 25 percent on Tuesday, fire officials said.

No evacuations had been ordered, but authorities said that if the fire crosses the Verde River (search), it could race into the towns of Pine and Strawberry, which have numerous vacation homes set in pine forest but somewhat less than 5,000 year-round residents.

The fire was still 20 miles southwest of Pine and Strawberry and 12 miles from the point where evacuations might be necessary, said Tom Berglund, a spokesman for the firefighters.

On the fire's western flank, firefighters held flames at bay across the road from the community of Black Canyon City (search). Town hall meetings were scheduled there as well as in Pine and Strawberry on Wednesday night to discuss the fire.

"We do have to be prepared, but there's no reason for panic," said Strawberry inn owner Cheryl Holland.

The blaze began June 21 as two lightning-started fires and destroyed 11 homes near Cave Creek, just north of Phoenix. The fire may have dealt a fatal blow to the world's largest saguaro cactus, which could be two centuries old.

The 46-foot Grand One, recognized in the National Register of Big Trees (search) for its height, mass of limbs and a base circumference of nearly 8 feet, was scorched.

"As much as I'd like to be optimistic, I'm not," said Tonto National Forest spokeswoman Emily Garber about the saguaro's survival.

The National Interagency Fire Center said Wednesday that 22 active large fires had burned across more than 905,000 acres in Alaska, Arizona, Colorado, Nevada, New Mexico and Utah.

In southern Nevada, good weather and a large firefighting force helped slow two huge wildfires burning Wednesday near the railroad town of Caliente.

"We have made progress," said Kathy Jo Pollock, a U.S. Forest Service (search) fire spokeswoman. "We've got 25 percent containment and we have really favorable weather conditions today."

With the fire lines still about 10 miles from town, Pollock said there was "no threat to the town."

At least 15 fires have been sparked by lightning since June 22 in the area northeast of Las Vegas.

Incident commanders were still mapping the burn area, which includes federally protected desert tortoise habitat on Bureau of Land Management and Forest Service land. Fires hopscotched across brittle desert grasses, mesquite, Joshua trees and mountain pines, officials said.

In Utah, relieved residents of the southwest community of New Harmony — nearly consumed by a wildfire — have returned to their homes.

"God was looking out for us. Our property was unharmed," said Emily Jones, whose home was within 50 feet of the fire.

Fire crews worked through the night Tuesday, turning back flames that came close enough to buckle the vinyl siding on one house. No homes were lost, and the fire was 50 percent contained by Wednesday.