A wildfire has destroyed dozens of houses overnight and charred land on the edge of the United States Air Force Academy in the state of Colorado, forcing more than 32,000 residents to flee the area, state officials say.
Thick smoke and towering flames on Wednesday kept officials from being able to fully ascertain the scale of the damage to Colorado Springs, the state's second largest city.
The wildfire doubled in size overnight, reaching a size of 62-square-kilometres, said Brett Waters, the emergency management director for the city.
Among those urgently moved out of the area on Tuesday evening were residents at the US Air Force Academy.
The fire burned about 10 acres (four hectares) of land along the southwest boundary of the academy's 72.5-square-kilometre boundary, but no injuries or damage to academy structures have been reported.
Steve Cox, an aide to Mayor Steve Bach, said on Wednesday morning that the blaze has consumed dozens of houses elsewhere. A precise figure was not available due to the intensity of the blaze.
Heavy smoke and ash has been seen billowing from the mountain foothills west of the city, and bright yellow and orange flames flared through the night.
Rich Brown, the city's fire chief, called the firestorm threatening Colorado Springs - which is in a metropolitan area of more than 650,000 people - "a monster" and said at this point flames were "not even remotely close to being contained".
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"It was like looking at the worst movie set you could imagine," Colorado Governor John Hickenlooper said after flying over the 23-square-kilometre fire late on Tuesday. "It's almost surreal."
After flames crested a ridge above the Air Force Academy campus on Tuesday, the institution told more than 2,200 residents to evacuate 600 households in one residential area.
About 90 firefighters from the academy and nearby fire departments were battling the encroaching flames.
Thunderstorms were expected to occur near the fire on Wednesday afternoon, but authorities said the rain could also bring unpredictable winds that would hinder firefighters' efforts near the city.
Firefighters have been battling the blaze for days amid record-setting heat and a prolonged drought along the interior of the western United States.
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 Asheville, North Carolina.
Elsewhere in Colorado, the 352-square-kilometre High Park Fire has destroyed 257 homes, authorities said. That fire was trigged by a lightning strike on June 9.
In central Utah, a fire has burned down 56 structures, the majority of which were homes, officials said on Wednesday.
A fire in Billings, Montana, has caused hundreds of families to flee and resulted in the destruction of at least 60 homes, authorities said.