Crews responded to the blaze in Estes Park, north of Denver, on Tuesday morning, and within hours officials say that it had grown quickly and significantly.
Mandatory evacuations were ordered for homes and businesses in Hermit Park in the southern part of the Rockies tourist town.
Authorities also put in place a voluntary evacuation order for the Meadowdale area.
Residents have been urged to move livestock and pets out of the area and prepare for more potential mandatory evacuations.
The fire is being driven by high winds, with gusts of up to 45mph being measured in the Little Valley area where the fire broke out, according to CBS4.
And the high winds are expected to continue there throughout the day.
“Residents and business occupants in the area of Hermit Park should evacuate due to immediate and imminent danger. Evacuate the area immediately and as quickly as possible,” Larimer County emergency managers wrote in an alert.
“Do not delay leaving to gather belongings or make efforts to protect your home or business. … Evacuating immediately not only supports your safety, but also allows emergency crews better access to the area.”
The fire was first reported to emergency services at around 7am and officials have not yet given a cause for it.
As of 5 November, the National Interagency Fire Center had reported a total of 48,725 wildfires across the us in 2021, which had burned more than 6.5m acres of land.
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