Show Low, Ariz. ? The huge wildfire that has charred hundreds of homes and vast stands of timber in eastern Arizona jumped a containment line Friday and inched its way up steep, rugged canyons toward 600 evacuated houses.

Firefighters used bulldozers to carve a five-mile line along the southern edge of Forest Lakes Estates, an evacuated subdivision 40 miles west of Show Low. Tankers buzzed overhead, dropping thousands of gallons of retardant on the northwestern flank of the 417,000-acre blaze.

The fire was about a mile from the subdivision Friday afternoon, and a plume of gray smoke spiraled hundreds of feet into the sky as the flames spread.

After several days of favorable weather, the humidity dropped and winds picked up Friday.

Other crews made their stand along a pair of roads, including Highway 260, just to the south of the subdivision. If the fire jumps the highway, it would spread into thick stands of ponderosa pine that stretch for 30 to 40 miles.

Wildfires have burned 2.6 million acres this year, far ahead of the 10-year average of 1 million acres, according to government fire managers.

Of 19 large fires in the Lower 48 states, eight were in Colorado. Fire officials there reported good news: The 137,000-acre Hayman fire, the largest in state history, is expected to be fully contained Sunday.

Near Durango, Colo., a 71,000-acre fire remained only 35 percent contained after destroying at least 56 homes.