The main part of the monster blaze remained south of State Route 260, but fire spokesman Jim Whittington said spot fires were developing across the highway, where crews worked furiously to extinguish them.

Whittington said that if firefighters could hold the line, if temperatures cooled and if the winds dropped overnight, they expected to make inroads against the flames, which were licking up through a series of finger canyons on the south side.

"It's just a matter of time, in the sense that if we can make until tonight with the fire across 260, it should lose its punch and we should be able to hold it tomorrow," Whittington said. "We've had a lot of active fire behavior today. It's something we're really concerned about."

Whittington said crews had been diverted from the mountain community of Show Low, about 35 miles (60 km) east of Forest Lakes, that had spent much of last week in danger of being overrun by the 420,000-acre (170,000 hectare) blaze before it was turned away.

The area scorched by the blaze measures 650 square miles (1,690 sq. km), - twice the size of the city of New York - and has a perimeter of about 200 miles (320 km).

HIGHWAY A CRITICAL FIRE LINE

"We've been pumping people into the (Forest Lakes) area since this morning," Whittington said. "We've also got three hot shot crews burning fire lines out by 260 and a 'dozer line around the community."

The massive fire began Friday about 5 miles (8 km) away from Forest Lakes, but high winds sent it charging through bone-dry pine forests toward the town before crews could slow it down.

About one-third of the crews, plus equipment, that once were dedicated to Show Low were now defending Forest Lakes, Whittington said. Evacuated Show Low residents could be back within days, he said, although no timetable has been set.

At Forest Lakes, meanwhile, crews were busy building fire lines, lighting backfire and dumping retardant and water on both side of State Route 260 in hopes of stopping the fire, which has been fueled by extreme drought conditions gripping the U.S. West.

If the fire jumps the highway, the concern also is that it could roar unabated through fuel-rich Ponderosa pine for at least another 30 miles (50 km), fire officials said.

More than 4,300 firefighters are on the scene of the massive blaze, and 500 more are expected to arrive by the end of Friday. In all, 423 homes have been destroyed.

Weather may help firefighting efforts with winds of 10 to 20 mph (15 to 30 kph) and mild summer temperatures. There was a 20 percent chance of thunderstorms, officials said.

No timetable has been set to allow the more than 30,000 people evacuated by the massive fire back into their homes. Motor tours are scheduled for Friday and Saturday for residents to see if their homes were spared, but they will not be allowed out of the vans.

Officials said the danger was too great to allow residents back into the area yet.

OFFICIALS OPTIMISTIC IN COLORADO

The biggest fire in Colorado's history, which has destroyed 133 homes, was expected to be fully contained by Sunday evening, three weeks and a day after it was ignited, fire information officer Randy Moench said.

The Hayman fire, 55 miles (90 km) southwest of Denver has scorched 137,000 acres (55,000 hectares). The U.S. Forest Service employee who allegedly started the fire on purpose was released on bail to a half-way house on Wednesday. She must stay away from drugs and alcohol and keep out of the forest.