A wildfire went out of control for a fourth day in the vertical mountains of southwestern New Mexico on Saturday, one of several fires that have extremes more than 200 square miles (520 square km) of rocky land in six U.S. states.

Hard works to hold the fires scattering in thinly populated areas of Arizona, Colorado, Michigan, Nevada, New Mexico and Utah have been injured by bursting winds and tinder-dry late-spring situations.

Various small towns, together with the historic Wild West mining town of Mogollon – now nearly a ghost town – were prepared to evacuate, as the scattering fire burnt down miles forest, brush and grass.

New Mexico’s Whitewater-Baldy Complex fire, which was begun by lightning 10 days ago, had expanded across 82,252 acres as of Friday and officials said the area could now be much larger than that.

"We know that there was noteworthy enlargement yesterday, but we don’t have a hard and fast number," said Fire Information Officer Dan Ware.

More than 580 firefighters and support crew have been fighting the fire.

"This is the largest show in the country right now in conditions of fire size. So a lot of assets are accessible to us. We’re just not sure we’ll be able to do a lot of flying," Ware said.

He said entrance to the fire had been the chief complexity as it was burning in very sharp, rough ground where firefighters were not able to cut through the brush and timber.

"Fire activity was so severe yesterday we had to pull crews out," he said. "We’re anticipating one more day like that today. With such high wind speed levels and low humidity there’s going to be big possibility for some major growth."

Smoke over Denver

Smoke from the New Mexico fire drifted north into the Denver metropolitan area on Saturday, as firefighters fought a separate wildfire flaming on the Utah-Colorado border.

That 2,800-acre fire was burning in a distant area near Paradox, Colorado, U.S. Forest Service spokesperson Steve Segin said.

He said there were only a few separated ranches in the area and no constructions had been lost so far, although the wind-driven fire was "very active." He said the cause was under investigation.

Most of western Colorado has been put under a "red flag" warning for wildfires due to hot high temperature, low humidity and high winds, according to the National Weather Service.

More than 1,000 miles (km) to the east, a wildfire in Michigan’s Upper Peninsula had grown a little to cover an area of more than 21,000 acres by Saturday, enlarging in a narrow band 11 miles long from about 14 miles north of the village of Newberry to Lake Superior, the state’s Department of Natural Resources said.

Dry circumstances posed troubles at the northeastern end of the blaze, where firefighters have intensified efforts dropping water from air tankers, Dean Wilson, a spokesperson for the state DNR’s western fire managing team, said on Saturday evening.

The DNR said access to what has been dubbed the "Duck Lake Fire" was hard and it was only 20 percent enclosed on Saturday morning. It said a number of structures had been smashed or ruined.

Wilson said good development had been made in tackling the south end of the fire and firefighters were setting up protective lines on the east and west sides.

There have been no additional evacuations and the protective lines around the Pike Lake area where there is a resort and Little Lake Harbor held on Saturday, Wilson said.

In Utah, officials said a wildfire burning on the west side of Promontory Point, the tip of a peninsula that juts into the Great Salt Lake, had grown to 4,200 acres, but was 50 percent contained.

The fire, contacted off by lightning on Thursday, was on fire ascending in the Promontory Mountains, on public and private land, the officials said. No constructions have been lost, they said.