Fast-moving Nevada wildfire destroys seven homes

Blazes in rugged, mountainous areas of Arizona, New Mexico and Colorado have already forced the evacuation of several small towns and torched more than 70 square miles (112 square km) of forest, brush and grass over the past 10 days.

The Arizona blazes were the first major wildfires in the Grand Canyon state this year after a record 2011 fire season in which nearly 2,000 blazes consumed over 1,500 square miles, according to the National Interagency Fire Center.

In northern Nevada near the California border, firefighters said seven homes were charred and another 100 homes were threatened from a new blaze that blackened 3,500 acres of brush and forest in Douglas County. No relief was in sight until Friday when rain and cooler temperatures are forecast.

More than 200 firefighters battled the blaze with bulldozers on the ground and helicopters from the air. Pictures in local media showed orange flames eating away at houses in the Topaz Ranch Estates community as smoke billowed in the background.

Even as fire crews struggled to contain the Nevada fire, more than 1,100 firefighters made slow progress against the most dangerous of the blazes burning in the U.S. Southwest, the so-called Gladiator Fire in Arizona.

That fire, which has charred about 23 square miles of ponderosa pine and brush some 40 miles north of Phoenix, was 19 percent contained on Tuesday, up from 15 percent a day earlier.

"Stronger winds and very low humidity, along with high temperature and extremely dry fuels made firefighters' work more difficult today," a fire incident statement said.

Authorities added that the fire had torched two more structures, bringing the total to six.

The blaze, which has cast a pall of grayish smoke over the northeast Phoenix valley over the past week, has forced the evacuation of about 350 residents of the old mining town of Crown King and three other tiny communities nearby.

Crews battling the largest of the four Arizona fires, the 25-square-mile Sunflower Fire, had succeeded in reinforcing control lines on Monday, although authorities cautioned that dead trees burning sporadically in the remote, rugged Tonto National Forest could lead to smoke in nearby communities.

Arizona's smaller Bull Flat and Elwood fires were mostly contained.

In New Mexico, authorities said the summer community of Willow Creek was being evacuated as a precaution because of a fire sparked by lightning burning in steep, rugged terrain of the Gila Wilderness area, where two separate fires have burned around 11 square miles.

In Colorado, crews had the 12-square mile Hewlett Fire burning in the Roosevelt National Forest almost completely contained, fire officials said.

(Reporting by Cynthia Johnston; Editing by Alex Dobuzinskis and Lisa Shumaker)