LAS VEGAS (AP) -- Firefighters lost ground Monday to two large wildfires burning through parched pine forests in northern and southern Nevada, including a nearly 24-square-mile blaze that forced more than 500 people out of homes in woodsy Mount Charleston enclaves near Las Vegas and a more than 27-square-mile fire in the Pine Nut Mountains southwest of Reno.
Homes were threatened, but more than 750 firefighters, including 18 elite Hotshot crews, were battling the Carpenter 1 Fire some 25 miles northwest of Las Vegas, said Jay Nichols, a U.S. Forest Service spokesman in the Spring Mountains National Recreation Area.
Gov. Brian Sandoval toured the fire area, visited an incident command post in Pahrump on Sunday, and applied for federal disaster aid. The Federal Emergency Management Agency promised Monday to reimburse the state for 75 percent of the cost of fire suppression efforts.
The Carpenter 1 was declared a top priority nationwide due to its size and the value of homes and structures at risk, said Suzanne Shelp, a Forest Service spokeswoman.
An influx of firefighters and equipment including bulldozers, seven helicopters, four air tankers and a DC-10 jet fire retardant bomber came as crews in Arizona neared containment of a deadly blaze that killed 19 Hotshot firefighters near Yarnell on June 30.
No injuries were reported and no structures burned in the fire, which started July 1 on the west side of Mount Charleston near Pahrump and quickly spread east into rugged terrain reachable only on foot. Officials said Monday that some $2.4 million had already been spent fighting the fire.
Smoke from the blaze created a towering white cloud that stretched northeast, visible from downtown Las Vegas. The Clark County Department of Air Quality issued a health advisory that officials said would remain in effect today through Sunday.
More than 400 homes in Trout, Kyle, Lee, Harris Springs and Lovell canyons were evacuated during the weekend, along with a Clark County-run youth correctional camp that houses 98 teenagers at a mountain elevation of almost 8,500 feet above sea level. State highways 156 and 157 were closed into the canyons, and evacuation shelters were set up at schools in Las Vegas and Pahrump.
Crews were also working to protect about 100 non-residential structures including barns, sheds and corrals, Nichols said.
Mount Charleston is a popular weekend getaway, where summer temperatures can be 15 to 20 degrees cooler than in Las Vegas, which has sizzled in the triple digits for more than 10 days.
Daytime high temperatures on the mountain were expected to decrease over the next few days after peaking at 90 degrees on Saturday, but firefighters were hampered by gusty winds and humidity levels in the single digits.
"This fire, these last few days and going forward, is going to depend on the weather," Shelp said.
In northern Nevada, the Bison Fire in the Pine Nut Mountains straddling the Douglas and Lyon county lines nearly doubled in size Monday from a day earlier as it burned through tinder-dry brush, dead trees and pinion-juniper forests.
The mountain range also stretches into Carson City. Late in the day, fire officials closed popular back-country roads leading from the state capital into the mountains because of the fire's path.
By afternoon the fire was estimated at 17,500 acres, or more than 27 square miles.
The blaze broke out July 4 and firefighters initially hoped to have it contained Monday. But those ambitions were dashed Sunday when strong winds fanned the fire into an inferno that pushed to the northeast and created a towering, swirling smoke plume seen for miles.
No homes have been lost, but officials said several old structures burned in the Slater Mine area.
More than 700 firefighters battled winds, low humidity and steep terrain to clear fire breaks through grass, pinion and juniper.
The Carpenter and Bison fires were each about 15 percent contained, with fire managers expecting crews to spend a week on both fire lines. Both blazes were sparked by lightning.
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Associated Press writer Sandra Chereb in Carson City contributed to this report.