SUPERIOR, Colo. — Could an underground coal fire be what sparked the state’s most destructive fire? That’s a question authorities are asking as they investigate several potential sources of the Marshall Fire.
Authorities confirmed that the now dormant Marshall Coal Mine near the area believed to be the starting point of the Dec. 30 Marshall Fire is among many other potential sources of the inferno that are being looked into.
The Marshall Coal Mine is located just south of the Marshall Mesa trailhead off Highway 93 and is one of 38 abandoned coal mines in the state that are listed to have some level of fire activity, according to a 2018 inventory report of Colorado underground coal mine fires.
"There are certain conditions inside the coal that make the coal spontaneously combust," said Jurgen Brune, a professor in mining engineering at the Colorado School of Mines.
On Saturday, police were blocking off the coal mine near the Marshall trailhead.
"If the surface gets hot, even hot enough from the sun, combustion can start and once it starts, it's very difficult to control and it can basically keep smoldering. And that can go on for decades," said Brune.
In 2005, a brush fire was ignited by a hot vent from the Marshall Coal Mine, which was quickly contained, according to the 2018 report. As a result, officials filled the vent with 275 tons of small rocks.
In 2016, authorities went back for touch-ups and to cover up small vents.
Maintaining mines with any level of fire activity is important. Former US Forest Service Branch Chief of the Rocky Mountains Region Jim Krugman points out that fires that spark from coal mines can be very complex.
Krugman served as the conduit between incident management teams in the 2002 Coal Seams Fire, which burned 12,000 acres and destroyed 29 homes in Glenwood Springs in 2002.
"For whatever reason, that coal steam decided it wanted to escape," said Krugman, discussing the 2002 Coal Seams Fire.
Flames appeared suddenly and "jumped into some brush that was frost killed and it was pretty much taking off in high winds in the canyon toward Glenwood Springs," said Krugman.
Krugman also stated that fire conditions in 2002 were similar to today. The state was just coming out of a drought and high winds and fuels on the ground were very apparent.
Analysis by the National Weather Service in Boulder released Jan. 12 looked into the 80-100 mile-per-hour winds, extreme drought conditions, and atmospheric conditions that helped turn the Marshall Fire into what officials have called a “firestorm.”
The Marshall Fire burned more than 6,000 acres in a matter of hours and destroyed nearly 1,110 homes and businesses, and damaged nearly 200 others. One man is confirmed to have died in the fire, and investigators are working to determine if bone fragments belong to a woman missing since the fire tore through Superior, Louisville and unincorporated Boulder County.
It's unclear when authorities will announce an official cause of the Marshall Fire. The Colorado Division of Fire Prevention and Control has asked for a team of local, state and federal investigators to put together a report on the conditions that caused the fire and the emergency response to the fire.
Among the coal mines investigation, authorities are also looking into whether a burning shed, downed power lines or human activity near the starting point of the fire were the possible cause.