Updated 5:07 PM ET
(CBS/AP) Searing, record-setting heat in the Western U.S. didn't loosen its grip on firefighters struggling to contain blazes in Colorado, Utah and other Rocky Mountain states.
Colorado has endured nearly a week of 100-plus degree days and low humidity, sapping moisture from timber and grass, creating a devastating formula for volatile wildfires across the state and punishing conditions for firefighters.
"When it's that hot, it just dries the fuels even more. That can make the fuels explosive," said Steve Segin, a fire spokesman for the U.S. Forest Service.
Much of Nevada, Utah, Wyoming and Colorado are under a red flag warning, meaning conditions are hot, dry and ripe for fires.
For the fourth straight day, Denver cleared 100 degrees and reached a record-high temperature of 105 on Monday. Other areas in the state have also been topping 100 degrees, including northern Colorado where the state's second-largest wildfire in history is burning.
And the scorching heat doesn't appear to be letting up soon. Temperatures across Colorado are expected to clear 100 degrees again on Tuesday. Segin said such prolonged heat is "extremely taxing" physically on firefighters, who are working long days and carrying heavy gear.
The wildfires are also posing a threat to tourism.
Several large wildfires across the West have placed some tourist destinations from Montana to New Mexico in danger just at the height of midsummer family road-trip season, putting cherished Western landscapes at risk along with hordes of vacationers.
In all, more than 1.3 million acres across the U.S. have been charred this year.
Heavy smoke billowed over an upscale neighborhood north of Colorado Springs on Tuesday as firefighters battled to keep a wildfire from burning houses and advancing toward the Air Force Academy.
The Waldo Canyon fire was less than 5 miles from the southwest corner of the academy's 28-square-mile campus, fire information officer Greg Heule says. Winds appeared to be pushing the fire to the west of the school.
Television video showed smoke and flames close to houses in a forested neighborhood northwest of Colorado Springs. There were no reports of homes burning.
At the High Park fire in northern Colorado, authorities increased the number of homes destroyed to 257, saying they found nine homes that hadn't been counted earlier.
The fires were among at least a half-dozen burning across the state.
On Monday a man accused of impersonating a firefighter appeared briefly in court for a procedural hearing. Authorities say Michael Maher, 30, faces misdemeanor charges of impersonating a public servant and obstruction of a fireman. The Fort Collins Coloradoan reports Monday that Maher is also being investigated for felony theft and attempting to influence a public servant.
Authorities say he was arrested on June 17 after allegedly crossing into the High Park fire area using a stolen government license plate and phony credentials. Maher also faces similar allegations at a March fire west of Denver.
Attorney Daniel Recht said in a statement that Maher idolizes firefighters and that he is "embarrassed" by his conduct.
Fire officials are much more optimistic that they'd get a handle on a destructive Sanpete County wildfire after making significant progress overnight.
Crews say Tuesday they have 15 percent containment on the Wood Hollow Fire outside Fountain Green, but they said that number could jump dramatically later in the day.
Interagency fire spokeswoman Dorothy Harvey confirms 25 to 30 homes have burned, and is not corroborating other reports that pegged the number ten times higher.
Search and rescue officials were going into the burned areas Tuesday to determine how many homes had been lost.
Harvey says the fire has remained mostly steady at about 60 square miles.
Hundreds of residents remained evacuated, although officials will assess Tuesday afternoon whether some can return.
The Little Bear file near Muidoso was 90 percent contained Tuesday morning, after having burned more than 44,000 acres.
Firefighters Monday were mopping up a small wildfire that threatened one of that state's top tourist attractions, El Santuario de Chimayo, a 19th century church north of Santa Fe. The church draws some 300,000 visitors a year and appeared to be out of danger Monday.
With the nation's privately-owned fleet of heavy air tankers already in use or unavailable, U.S. Forest Chief Tom Tidwell said his agency had to call on C-130 military tankers to help. The order came as new fires started in Colorado, Utah, Alaska and Arkansas.
Lewis and Clark County County officials began evacuating additional residences as strong winds fanned a 1,400-acre fire north of Helena that has destroyed at least four houses.
Winds gusting up to 52 mph were recorded early Tuesday afternoon, pushing the fire to the northeast.
Sheriff Leo Dutton says they're evacuating houses a half mile ahead of where they expect the fire to go, but he says that's tough to predict.
The fire started shortly after 4 p.m. Monday. Dutton says the fire was human-caused, but was an accident.
One of the burned homes belonged to a soldier who is deployed with the National Guard in Afghanistan.
In Gorman, north of Los Angeles, a nearly 700-acre brushfire is burning but authorities say no homes are threatened and they hope to contain it by noon Tuesday.
The blaze in Los Padres National Forest was nearly 80 percent contained Tuesday morning. Fire spokesman Manuel Madrigal said the flames have been reduced to a few smoldering trees and hotspots.
More than 600 firefighters and some water-dropping helicopters are on the scene near the Hungry Valley State Vehicular Recreation Area.
The fire began Saturday in a Ventura County campground. The cause is under investigation.
South of that blaze, a 12-acre fire is burning in steep, rocky terrain in San Bernardino County's Lytle Creek. It's 70 percent contained after briefly threatening five cabins over the weekend.
The Fairbanks Daily News-Miner reports that 17 new fires were reported Sunday, with 13 of them caused by lightning strikes. One of the fires was burning only a few miles west of the Parks Highway between Nenana and Healy.
Officials with the state Division of Forestry say more than 100 firefighters were battling the blaze, which started as the different fires on Saturday but merged into one on Sunday.
A late-afternoon thunderstorm produced more than 2,000 lightning strikes on Saturday, most of which were south of Fairbanks near the Alaska Range.
A fire about 14 miles south of Clear Air Force Base has burned more than 8,200 acres and is zero percent contained.
The first major wildfire of the season in western Wyoming has burned about 300 acres in the Bridger-Teton National Forest.
The Fontenelle Fire is located about 30 miles northwest of LaBarge and is burning in heavy and down timber. It was discovered late Sunday afternoon.
Forest spokeswoman Mary Cernicek says 60 firefighters and three helicopters are on the scene now, but more firefighters have been requested.
There are no structures in the vicinity, but Cernicek says fire managers have decided to fully suppress the fire.
In east-central Wyoming, about 620 firefighters are still working to contain a wildfire burning in the Medicine Bow National Forest. The Russell's Camp fire has burned about 8 square miles. It is 35 percent contained.
Red flag warnings are posted for most of the state.
More than 100 firefighters remain around the perimeter of an eastern Arizona wildfire as they wait for possible scattered thunderstorms.
The U.S. Forest Service said late Monday that containment against the Poco Fire just outside of Young is still at 65 percent.
Crews continue to check for hot spots and are prepositioned for potential lightning strikes.
Andy Mandell, the incident commander trainee, said some trees are smoldering.
The Poco Fire was burned nearly 12,000 acres since it began on June 14.
Five firefighters have been injured and no structures have burned.