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February 10, 2021

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Public Information Unit, 303-441-1500

Investigation into the cause and origin of the Calwood Fire is complete

Boulder County, Colo. - The Boulder County Sheriff’s Office has completed their investigation into the cause of the Calwood Fire. Based on physical evidence and interviews the cause of the fire is undetermined.

Sheriff’s detectives began their investigation into the cause and origin of the fire immediately after assisting with the evacuations of homes in the path of the fire. Detectives worked with investigators and personnel from the Boulder County Multi-Agency Fire Investigation Team, U.S. Forest Service, Bureau of Alcohol Tobacco Firearms and Explosives, Colorado Division of Fire Prevention and Control, and the National Oceanic and Atmospheric Administration.

Investigators interviewed numerous people during investigative efforts and followed up on tips from community members. Interviews included landowners, neighbors, and recreators who had been in the area before and immediately after the fire started, as well as from federal firefighting personnel who were overhead in aircraft within minutes after the fire was initially reported. Investigators were able to determine the fire started within an area within a 500-foot radius, however there was no known cause established.

The Lefthand Fire is still under investigation by U.S. Forest Service investigators. Sheriff’s investigators assisted with early portions of that investigation; however the entire investigation is being handled by the U.S. Forest Service at this time.

Investigators do not believe the fires are related.

The associated Boulder County Sheriff's Office case number is: 20-4630.

Additional Fire Information:

The Calwood Fire was first reported to the Boulder County Sheriff’s Office Communications Center on Saturday, October 17 at 12:06pm. The initial report indicated smoke and was soon confirmed as a one-acre wildfire outside of Jamestown in the vicinity of the Cal-Wood Education Center off County Road 87. This fire would become known as the Calwood Fire. The fire grew quickly due to the dry conditions and strong west winds; homes as far as Hygiene were part of the initial evacuation area due to the rapid rate of spread of nearly a thousand acres per hour.

On Sunday, October 18 at approximately 12:30 p.m., the Communications Center received a report of a second wildfire outside of Ward. This fire would become known as the Lefthand Canyon Fire.

The Calwood Fire burned 10,113 acres, had 26 structures lost or damaged, and reached 100% containment on Saturday, November 14. The Lefthand Canyon Fire burned 460 acres, had no structures lost, and reached 100% containment on Thursday, October 22. The estimated cost of resources spent on the fires is $6.6 million. There were no fatalities resulting from either fire.

The Communications Center sent evacuation orders to 4,925 contacts and evacuation warnings to 4,773 contacts. An estimated 967 animals were sheltered between the Boulder County Fairgrounds (562), Longmont Humane Society (96), and the Humane Society of Boulder Valley (27). In coordination with the American Red Cross, approximately 1,800 people were sheltered in eight different hotels. This number includes evacuees from surrounding wildfires outside of Boulder County that were occurring at the same time.

As the fires grew resources from nearly every first responder agency in Boulder County responded to assist with the suppression efforts, evacuations, roadblocks, etc. The Type III Boulder Incident Management Team and the Type II Team Black Incident Management Team were also activated for the fires.


Carrie Haverfield, Public Information Specialist