Wind-driven wildfires in Colorado burn hundreds of homes, force evacuations

An estimated 580 homes, a hotel and a shopping centre have burned and tens of thousands of people were evacuated in wind-fuelled wildfires outside Denver, officials said Thursday evening.

At least one first responder and six others were injured, though Boulder County Sheriff Joe Pelle acknowledged more injuries and deaths could be possible due to the intensity of the fires that quickly swept across the region as winds gusted up to 170 km/h.

The first fire erupted just before 10:30 a.m. local time and was "attacked pretty quickly and laid down later in the day and is currently being monitored," with no structures lost, Pelle said.

A second wildfire, reported just a half hour later, "ballooned and spread rapidly east," Pelle said. The fire spans 6.5 square kilometres and has engulfed parts of the area in smoky, orangish skies and sent residents scrambling to get to safety.

The activity of the fires, which are burning unusually late into the winter season, will depend on how the winds behave overnight and could determine when crews are able to go in and begin assessing the damage and searching for any victims.

"This is the kind of fire we can't fight head on," Pelle said. "We actually had deputy sheriffs and firefighters in areas that had to pull out because they just got overrun," he added.

Louisville, Colo., with a population of about 21,000, and Superior, Colo., with 13,000 residents, were both told to evacuate. The neighbouring towns are roughly 30 kilometres northwest of Denver.

Several fires started in the area Thursday, at least some sparked by downed power lines.

Colorado's Front Range, where most of the state's population lives, had an extremely dry and mild fall, and winter so far has continued to be mostly dry. Snow was expected Friday in the region though.

Wind and smoke reduce visibility

One video captured by a bystander outside a Superior Costco store showed an apocalyptic scene, with winds whipping through barren trees in the parking lot surrounded by grey skies, a hazy sun and small fires scattered across the ground.

Leah Angstman and her husband saw similar skies while returning to their Louisville home from Denver International Airport after being away for the holidays.

As they were sitting on the bus heading toward Boulder, Angstman recalled instantly leaving clear blue skies and entering clouds of brown and yellow smoke.

"The wind rocked the bus so hard that I thought the bus would tip," she wrote in a message to The Associated Press.

The visibility was so poor that the bus had to pull over and they waited a half-hour until a regional transit authority van escorted them to a turnaround on the highway. There, Angstman saw four separate fires burning in bushes across the freeway.

"The sky was dark, dark brown, and the dirt was blowing in swirls across the sidewalk like snakes," she said.

Angstman later ended up evacuating, getting in a car with her husband and driving northeast without knowing where they would end up.

State of emergency declared

Vignesh Kasinath, an assistant professor of biochemistry at the University of Colorado in Boulder, fled a neighbourhood in Superior with his wife and her parents. Kasinath said the family was overwhelmed because of the sudden evacuation warning and anxious from the chaos while trying to leave.

"It's only because I am active on Twitter I came to know about this," said Kasinath, who said he did not receive an official evacuation notice from authorities.

The fires prompted Colorado Gov. Jared Polis to declare a state of emergency, allowing the state to access disaster emergency funds.

The evacuations come as climate change is making weather more extreme and wildfires more frequent and destructive, scientists say. A historic drought and heat waves have made wildfires harder to fight in the U.S. West.