Steamboat Springs The source of the wildfire near Glenwood Springs is common in Northwest Colorado.
The Coal Seam fire, burning about 100 miles south of Steamboat Springs near Glenwood, started from an underground coal seam that has been burning for years.
Coal seams, which are deposits of coal in the ground, are common in Routt County, an area that mines more coal than any other county in Colorado.
When conditions are right in abandoned coal mines, coal seams can ignite, usually underground, and burn for an extended period of time.
Routt County Commissioner Dan Ellison said he knows of one coal seam fire burning in Moffat County but doesn't know of any in Routt County.
That fire is off Moffat County Road 13, near the old Eagle Mine. Occasionally, Ellison said, smoke is seen rising from the ground in that area.
"It has been burning as long as I've been around here that's around 27 years," Ellison said.
Coal seam fires are common in places where there are historic coal mines, such as most of the Colorado Rocky Mountains. Ellison said he doesn't know of any coal seam fires in Routt County but said he wouldn't be surprised if there were some.
Though coal seam fires are common, it isn't common for wildfires to be sparked by them, Ellison said.