June 25 (UPI) -- Southern Utah's wildfire is the largest in the United States one week after it started.
The blaze -- called the Brian Head Fire -- had consumed 40,148 acres by Saturday night in Utah, including 12,500 new acres since Thursday morning, according to Iron County Emergency Management.
The fire, which was ignited by a resident burning weeds and has been fueled by hot, dry conditions and strong wind, has been 8 percent contained.
The blaze straddles Iron and Garfield counties. Since the fire began on June 17 in the resort town of Brian Head, several hundred people have been evacuated from their homes.
Destroyed were 13 residences and eight buildings.
About 1,000 personnel are fighting the fire. A Type 1 incident management team -- a squad with the highest level of experience — arrived Saturday afternoon and joined the current Type 2 team.
"Because of the size of the fire and the complex logistics of dealing with such a large area of impact, travel, and communications, the fire will be divided operationally," according to a release by the Utah Division of the Forestry Fire State Lands.
On Saturday afternoon, northerly winds caused the fire to move across State Route 143 near Mammoth Creek and also near Prince Mountain.
The fire in southern Utah is one of 18 large fires burning in the Southwest, including six in Arizona, two others in Utah, three in California, three in New Mexico, two in Nevada and one in Oregon.
The fires are fueled by triple-digit temperatures and dry conditions.
In southern Arizona, the Frye Fire has covered nearly 30,000 acres as of Saturday afternoon and was 29 percent contained, the forest service at Coronado National Forest said. More than 800 personnel are battling the fire.