Governor Jared Polis declares a state of emergency as the National Weather Service warns of ‘life-threatening situation’ in affected areas in US.

Hundreds of homes have been destroyed and tens of thousands evacuated in Colorado, United States, after wildfires driven by high winds engulfed two towns near the state capital, Denver.

At least six people and one first responder were injured on Thursday, though officials believe there could be more casualties due to the strength of the fires that quickly swept across Boulder county. With winds gusting up to 169 kilometers per hour (105 milers per hour), the National Weather Agency warned of a “life-threatening situation” in some areas.

Authorities ordered evacuations for Louisville, which has about 21,000 residents, and Superior, home to 13,000 people and a suburb of Boulder. The neighbouring towns are roughly 32km (20 miles) northwest of Denver, a city of more than 715,000 people where a towering plume of smoke was visible.

“We know that approximately 370 homes in the Sagamore subdivision … have been lost. There’s a potential of 210 homes lost in Old Town Superior,” Boulder County Sheriff Joe Pelle told a news conference on Thursday.

“Due to the magnitude and intensity of this fire, and its presence in such a heavily populated area, we would not be surprised if there are injuries or fatalities,” he said.

Residents evacuated fairly calmly and orderly, but the winding streets in the suburban subdivisions quickly became clogged as people tried to get out. It sometimes took cars as long as 45 minutes to advance just a few hundred metres.

Structures burn as a wind-driven wildfire forced evacuation of the Superior suburb of Boulder, Colorado, on Thursday [Trevor Hughes/USA Today via Reuters]

The first fire erupted just before 10:30am 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 after 11am, “ballooned and spread rapidly east”, Pelle added. The blaze spans 6.5 square kilometres (2.5 square miles) 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.

According to the Denver Post, the fire is the most destructive in Colorado’s history in terms of the number of homes destroyed.

Governor Jared Polis declared a state of emergency to allow the use of disaster funding to support emergency response efforts and the mobilisation of the Colorado National Guard and other state resources as needed.

A nearby portion of the US highway also was reported shut down because of a fire.

Very strong winds fueling the #marshallfire. Never a good sign when radar shows a smoke plume this strong.

Please heed all evacuations associated with this fire. Follow @BoulderOEM for latest evacuations and official fire info. #COwx pic.twitter.com/EzYy80xOBd

— NWS Boulder (@NWSBoulder) December 30, 2021

The fires on the outskirts of the Denver metropolitan area, left bone dry from an extreme drought gripping eastern Colorado, followed several days of heavy snow in the Rocky Mountains to the west.

Congressman Joe Neguse, who represents Colorado’s 2nd District, called the wildfires “unprecedented.”

“]The wildfires] have just created a level of devastation and destruction that our state has not experienced before,” he told CNN.

The US Federal Emergency Management Agency approved funding for Colorado’s firefighting teams on Thursday.

“The authorization makes FEMA funding available to pay 75 percent of the state’s eligible firefighting costs,” the agency’s statement said

A house burns as a wind-driven wildfire forced evacuation of the Superior suburb of Boulder on Thursday night [Eric English/Reuters]