With the worst wildfire in Arizona history gaining ground, firefighters fought back with flames, helicopters and bulldozers to try to fend off a galloping blaze that has burned 375,000 acres and destroyed at least 390 homes.

After witnessing the destruction by air Tuesday, President Bush declared the region a disaster area and told evacuees at a high school in Eagar that people across America are pulling for them.

"They understand that a lot of you are living in tents when you'd rather be in your own bed," Bush said. "They cry for you and they hurt with you."

Some of the 30,000 people who evacuated cities and towns threatened by flames wept and rejoiced Tuesday as they learned the fate of their homes.

Some worried whether their houses still stood. Some had had it with the shelters where they have been forced to seek refuge. Many were sick and tired of waiting.

"I can't get any sleep in the dorms because there are people drinking and kids screaming," said Heber-Overgaard resident Shirley Lagrosa, who was at a shelter at an area high school. "Being here makes you feel numb and depressed. It's just too much."

Weary residents anxiously lined up for an opportunity to phone for information to find out if their houses had survived.

At the shelter in Eagar, Lois Trimble exulted in learning that her Pinedale house had been spared.

"Oh, praise God! Our house is still there!" she said in tears as she hugged friends and strangers. "I put angels outside the house when I first built it because I was afraid of people stealing things. I just knew the angel would watch over us."

Since Sunday evening, the fire had stood at the outskirts of Show Low, a town of 7,700 in eastern Arizona.

Firefighters were able to scorch a half-mile barrier of forest and meadow at Cottonwood Canyon on Tuesday to deprive the blaze of fuel and thwart its march into town.

"This was our best place to make a stand," said Paul Schmidtke, a fire spokesman with the Bureau of Land Management.

In a single week, the blaze had charred 586 square miles -- an area larger than Los Angeles -- and there is no containment in sight. Smoke has spread across the Southwest and was seen as far south as Las Cruces, N.M.

It is by far the biggest and most damaging blaze of a fire season that has shown no signs of getting better.

On the western edge of Show Low, bulldozers dug a 90-foot-wide scar in the ground and crews set fires to burn their way back to the larger blaze, depriving it of new fuel as helicopters dumped thousands of gallons of water and retardant on flames.

Firefighters trying to spare the town from disaster cut down trees close to homes, removed firewood and moved propane tanks away from homes. Sprinklers watered down houses close to the fire line to prevent stray embers from igniting.

"We're still ready," said Phoenix Fire Capt. John Brunacini. "We're like ducks on water, calm on top but our feet are going underneath."

The wildfire, formed by two smaller blazes that merged Sunday, is the largest in Arizona history and one of the worst the West has ever seen. A lost hiker started one fire trying to signal for help. The other fire is believed to have been ignited by humans, but the cause has not been determined.

The fire has done more damage than the Los Alamos, N.M., blaze that destroyed about 220 homes and businesses two years ago.

In Colorado, hot weather and shifting wind made it another miserable day for firefighters near Durango, where new flames damaged buildings, closed down a highway and forced more evacuations.

A fire there has burned nearly 67,000 acres, at least 45 homes and damaged hundreds of power poles, cutting off electricity to more than 500 abandoned homes.

Southwest of Denver, crews had 70 percent containment of a 137,000-acre fire that has destroyed at least 133 homes and cost more than $26 million to fight.

The Associated Press contributed to this report.