Residual heat from tree debris burned in December 2010 may have ignited a Duchesne County wildfire that destroyed homes in June, according to a state report.
But the final report on the Church Camp Fire is not conclusive. Investigators for the Utah Division of Forestry, Fire and State Lands wrote it is "highly unlikely" a fire could reignite after 18 months, but said there was no evidence of lightning, arson or anything else that could have started the blaze.
"One single log or root can smolder underground just as long as it's getting enough air to survive," said Jason Curry, one of the fire investigators, in an interview Tuesday.
The Church Camp Fire, named for a nearby youth camp, was reported June 24 about 19 miles southwest of Duchesne near U.S. 191 in Argyle Canyon. It burned 7,211 acres, destroyed 15 homes, and cost $5.7 million to fight.
Trees in the area had been cut for logging. The fire ignited on the west side of a slash pile that, according to staff from the Utah School and Institutional Trust Lands Administration, was burned on Dec. 2, 2010.
One cabin owner told investigators that two weeks before the Church Camp Fire ignited, he and his daughter visited the slash pile. The cabin owner said he stepped in a 1Â½-inch pile of fluffy white ash that appeared to have been recently burned. The cabin owner said he suspected dirt around the pile was helping retain heat.
Also, another slash pile burned in the fall of 2011 several miles west of the Church Camp Fire reignited in the spring. The report implies this is evidence the 18-month-old burned slash pile could have reignited, too.
The investigators, who included Forestry, Fire and State Lands Director Dick Buehler, said there was no recorded lightning in the area nor was there evidence of a camp fire, incendiary devices, fireworks, power lines, children playing with matches, heavy equipment or other devices typically associated with igniting wildfires.
"Based upon these facts and observations," investigators wrote at the end of their report, "it must be concluded that the only possible cause of the Church Camp Fire was residual heat from the slash pile, which is highly unlikely given the facts and circumstances outlined in this report, or arson, which cannot be substantiated."