The figure comes from Mayor Steve Bach, citing preliminary damage reports.

If those figures hold up, the tally of lost homes in and around Colorado Springs would make the so-called Waldo Canyon Fire the state’s most destructive on record, surpassing the 257 homes consumed in recent weeks by a much larger blaze north of Denver near Fort Collins.

While no deaths or serious injuries have been reported from the blaze so far, Colorado Springs Police Chief Peter Carey said authorities were seeking the whereabouts of some people he described as “unaccounted for,” though he did not give a number.

A police spokeswoman, Carrie McCuffland, said there were no specific reports from citizens of missing people, and that the unaccounted-for list consists of individuals who apparently neglected to register with the city or the American Red Cross as evacuees.

“Every indication is that there are no casualties,” McCuffland told Reuters.

Authorities earlier acknowledged the loss of hundreds of homes in Tuesday’s firestorm, but the damage toll released by the mayor at an afternoon news conference on Thursday gave the first firm picture of the full extent of the devastation.

President Barack Obama plans to visit Colorado Springs on Friday to meet with firefighters and tour the ravaged zones.

The grim news came as lighter winds helped firefighters battling to contain the inferno that had roared unchecked through residential neighbourhoods in the northwestern corner of Colorado Springs and nibbled at the fringe of the US Air Force Academy campus.

The academy welcomed over 1000 new cadets on Thursday, despite the fire, bringing them to a portion of the facility far from the smoke, base spokesman Harry Lundy said.  

For the first time since the blaze erupted on Saturday, a red-flag warning for heightened fire hazards was lifted for the Colorado Springs area.

“We had a pretty good day on the line today. There was minimal fire growth,” incident commander Rich Harvey said.

But anguish and frustration ran high among many of the estimated 35000 residents who remained under evacuation orders.

“You don’t have the authority to keep me out of my house,” David Dougherty, 45, a retired member of the Armed Forces, shouted out during the news conference. “I understand they’re trying to save lives, but some of us don’t need to be saved.”

Dougherty said he believes his dwelling is still intact and wants to be let back in to the evacuation zone to secure his home and his belongings. Police reported at least one arrest for burglary in an evacuated neighborhood.

Bret Waters, the city’s emergency management director, said some evacuees would be allowed to return beginning at 8 p.m. local time Thursday.

Corralling the flames

The Waldo Canyon blaze remained a formidable force, with fire crews managing to carve containment lines around just 10% of its perimeter by Thursday afternoon — a fraction of the sprawling fire zone but still double the previous day’s total, officials said.

Searing temperatures and strong, erratic winds in recent days stoked the blaze, which has burned at least 18500 acres (7487 hectares) of timber and brush, much of it in the Pike National Forest to the west of the city that lies at the base of the famed Pikes Peak mountaintop.

Firefighters on Wednesday pushed back a spot fire in a vacant corner of the Air Force 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 Bach after touring the Mountain Shadows subdivision, which bore the brunt of the destruction.

Colorado wildfires have killed four people this year in what the governor called “the worst fire season” in state history.

Earlier this month, the High Park Fire west of Fort Collins and north of Denver killed one woman while leaving 257 homes destroyed and more than 87000 acres (35000 ha) blackened. That blaze, ranked briefly as Colorado’s most costly in property damage, was listed as 75% contained on Thursday. 

The cause of the Waldo Canyon Fire remained under investigation, authorities said. FBI’s Denver office issued a statement on Thursday saying its agents were “working closely with local, state and federal law enforcement to determine if any of the wild land fires resulted from criminal activity.”

The fire menacing Colorado Springs follows a recent string of suspected arson fires in a neighbouring county, but officials said they had no indication that the Waldo Canyon blaze was deliberately set.

More than 1200 personnel, supported by heavy air tankers and helicopters, are assigned to the blaze, Harvey said.