Heavy smoke and ash billowed from the foothills west of the city as the Waldo Canyon Fire became the top challenge for the nation's firefighters.
“It was like looking at the worst movie set you could imagine,” Gov. John Hickenlooper said after flying over the fire late Tuesday. “It's almost surreal.”
With flames cresting a ridge high above its campus, the Air Force Academy told more than 2,100 residents to evacuate.
Elsewhere, fleeing residents covered their faces with T-shirts and bandanas to breathe through the smoke.
Throughout the West, firefighters have toiled for days in searing, record-setting heat against fires fueled by prolonged drought. Most, if not all, of Utah, Colorado, Wyoming and Montana were under red flag warnings, meaning extreme fire danger.
The nation is experiencing “a super-heated spike on top of a decades-long warming trend,” said Derek Arndt, head of climate monitoring at the National Climatic Data Center.
In central Utah, authorities found one woman dead Tuesday when they returned to an evacuated area, marking the first casualty in a blaze that consumed at least two dozen homes. Sanpete County sheriff's officials said they hadn't identified the victim.
The cause of the Waldo Canyon fire remained under investigation.
In northern Colorado, another fire has destroyed 257 homes, authorities said. That fire was triggered by lightning June 9.