Some of the hundreds of totally destroyed homes are seen in the aftermath of the Waldo Canyon fire in Colorado Springs, Colorado. Cooler temperatures and lighter winds helped firefighters on Thursday in the battle against the fire, which has destroyed hundreds of homes and forced more than 35 000 people to flee.

Colorado Springs - Lighter winds helped firefighters as they battled on Thursday to contain an inferno on the edge of Colorado Springs and near the Air Force Academy that has torched hundreds of homes and forced about 35 000 people to flee.

For the first time in five days, a red flag warning, which indicates weather that could increase wildfire activity - was not posted in the Colorado Springs area where the so-called Waldo Canyon Fire has burned since Saturday, authorities said.

“It definitely increases their (firefighters') morale because it means they can work safer, it means that they can most likely get more done today,” fire information officer Rob Deyerberg said.

The Waldo Canyon blaze, however, remained devastating and only five-percent contained, officials said. Searing temperatures and strong winds in recent days fuelled the blaze, which has burned 18 500 acres, destroyed homes on the wooded fringe of Colorado's second largest city and threatened the Air Force Academy.

Firefighters on Wednesday pushed back a spot fire in a vacant corner of the academy, but some residential neighbourhoods in and around Colorado Springs were harder hit.

“There was nothing left in some areas, burned out foundations that were smouldering. It looked like a nuclear weapon had been dropped. It's as close to hell as I could imagine,” said Colorado Springs Mayor Steve Bach, who toured the heavily damaged Mountain Shadows subdivision.

Authorities have not released an official count of the number of homes destroyed in the Waldo Canyon fire but said the figure was in the “hundreds.” A more complete damage assessment was expected later on Thursday.

Colorado wildfires have killed four people this year in what the governor called “the worst fire season” in state history. No injuries from the Waldo Canyon fire have been reported.

“Yesterday was a good day, and firefighters have made progress,” incident commander Rich Harvey said at a news briefing on Thursday. “Now we're going to go after it aggressively.”

More than 1 200 personnel, supported by heavy air tankers and helicopters, are assigned to the blaze, Harvey said.

On Thursday morning, Colorado had a total of nine air tankers, including four Lockheed C-130s, available to drop fire retardant on blazes in the state, said Jennifer Jones, spokesperson for the National Interagency Fire Centre.

Despite the blaze, the Air Force Academy welcomed over 1 000 new cadets on Thursday, bringing them to a part of the facility far from the smoke, Academy spokesperson Harry Lundy said.

Winds at the Waldo Canyon fire were only about 19km/h, fire officials said. By comparison, winds in the area on Tuesday reached speeds of 64km/h, said Alex Sosnowski, expert senior meteorologist for

President Barack Obama planned to visit the Colorado Springs area on Friday to meet with firefighters and tour the ravaged zones. More than 35 000 people have been ordered to evacuate, officials said.

Sporadic, light rainfall fell in parts of Colorado Springs on Thursday. Despite the drop-off in wind speeds over the last two days, forecasters said high temperatures would remain a problem.

On Thursday, temperatures were expected to reach the mid-30s (Celsius), Sosnowski said. “Essentially they're going to be stuck in a sea of hot air ... for the next two to three weeks at least,” he said.

The Waldo Canyon fire was one of a dozen blazes across Colorado on Thursday. The High Park fire, which burned 257 homes west of Fort Collins and north of Denver making it the state's most destructive fire in terms of property lost, was listed as 75 percent contained on Thursday.

No red-flag warning was issued around the area of the 87 284-acre High Park fire for the first time in five days as well. Some evacuation orders were lifted, and some residents were allowed to return to their homes.

There are 42 large, active wildfires burning in the United States, with Colorado and Montana suffering the most, Jones said.

Wildfires also are raging in New Mexico, Arizona and Utah, but with 1.6 million acres burned across the United States in 2012, the fire activity this year still ranks below the 10-year average for the nation, federal records show. - Reuters