The Ice Fire, near the popular Ice Lakes Trail west of Silverton in 2020, was likely caused by humans.
The 596-acre fire burned for about a week in October 2020 and led to a helicopter rescue of 28 stranded hikers. It started at a large, flat boulder in a meadow near the treeline about 75 feet from the Ice Lakes Trail, according to a U.S. Forest Service investigation released in early August.
The boulder was a popular rest stop along the trail, the report said.
“The only probable factor as to contributing to the start of the fire is human in nature,” the Forest Service report said. “No evidence or conclusive evidence was found in the point of origin. Therefore, the cause of the Ice Lakes Fire is inconclusive.”
Investigators ruled out campfires, fireworks, burning debris and natural causes, such as lightning. Because no road or railroad was nearby, mechanical causes also were excluded.
“Though no cigarette butt(s) could be found at the specific origin, this is the leading theory,” the report said.
Children were listed as a possible cause because of the boulder’s proximity to the trail.
The Ice Lakes Trail is one of the most popular and heavily used trails in Southwest Colorado. It starts at an elevation of 9,840 feet and climbs about 2,500 feet to two turquoise alpine lakes, Ice Lake and Island Lake.
The Ice Fire was spotted Oct. 19 about half a mile up the trail. Soon after, Silverton-San Juan County Fire and Rescue crews responded to the area, about 5 miles west of town.
The fire spread across the trail and headed uphill, trapping hikers near the burning area until they were rescued by helicopter.
By Oct. 26, the fire was 100% contained, and a winter storm knocked it out for good.
The trail, however, was heavily damaged by the blaze and closed for the summer. Weakened trees, erosion and flash floods posed safety hazards that made it too risky to open the trail, according to the Forest Service.
The closure order for the trail expires Sept 15. Forest Service managers could extend the closure order if area hazards exist that pose a risk to safety. The trail will reopen only when the area is deemed safe for public entry, said Rebecca Robbins, Forest Service spokesperson.
Editor’s note: This story was updated to clarify the Ice Lakes Trail closure expires Sept. 15. The trail will reopen only when deemed safe for the public.