Rowdy Alexander observes from the top of his horse while fire burns on a hill overlooking the Northern Cheyenne Indian Reserve near Lame Deer, Mont., August 11, 2021.

Authorities investigating the cause of a wildfire that destroyed more than 1.000 buildings last month in Colorado are working to establish the possibility that the flame is linked to underground coal fires that have been simmering in ancient coal mines around it.

It remains unknown what prompted December’s fire that developed into the most destructive in Colorado history, but Boulder County authorities have said they are looking at the area’s abandoned coal mines as one of several possible causes, along with power lines, human activity and other options.

Could red-hot coal have brought about such a fire?

History shows that the answer is “Yes,” with at least two fires that have ravaged Colorado in the past 20 years as a result of landfires spreading to the surface.

Following last summer’s fires, local authorities in Montana plan to map seams of flames in the state’s southeast with the help of a federal grant in the coming months.

Colorado authorities were monitoring at least 38 underground coal fires between now and 2019.

In 2016, when federal officials announced that the state had taken control of the site, workers dug and filled up two areas where soil had subsided from the fire.

Tetra Tech

Tetra Tech, Inc. is an American Pasadena, California-based consulting and engineering services firm. The company provides consulting, engineering, program management, (wikipedia)

Northern Cheyenne Indian Reservation

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The Northern Cheyenne Indian Reservation is home of the federally recognized Northern Cheyenne tribe. Located in southeastern Montana, (wikipedia)