The Colorado Avalanche Information Center has released its final report about an avalanche southwest of Ophir that killed a solo backcountry snowboarder March 17.
Devin Overton, 29, of Telluride, died after triggering an avalanche that caught and buried him at 13,000 feet elevation in the Poverty Gulch area east of Trout Lake.
Telluride Helitrax spotted the fresh avalanche below Pilot Knob with tracks going into the slide area, but not out. They landed, and two guides found Overton’s body by using a transceiver search. He was buried about 6½ feet deep.
Helitrax flew in four additional rescuers, and the six worked for about an hour to excavate Overton.
In the final report, CAIC investigators Jeff Davis and Jeremy Yanko reconstructed Overton’s route based on his tracks and GPS data and analyzed the avalanche incident.
Before triggering the avalanche, he had ascended and descended two southwest-facing couloirs between Yellow Mountain and Pilot Knob.
He then traveled toward the more west- and northwest-facing slopes below Pilot Knob, and caused an avalanche. It broke 20 to 36 inches deep on a layer of faceted crystals and ran 1,000 vertical feet on a northwest-facing slope over two cliff bands.
“Overton was an accomplished backcountry snowboarder with a high risk tolerance, and was comfortable traveling alone,” the CAIC report said.
The Colorado Avalanche Information Center rated the backcountry avalanche danger in the North San Juan zone at “moderate,” Level 2 of 5, at all elevations on the day of the slide. Persistent slab avalanches were the main avalanche problem.
The weather January through February was dry and windy, with cold, clear nights, the CAIC report said.
A layer of near-surface faceted crystals formed in the upper snowpack. That layer was buried by snowfall Feb. 21. Four storms followed, and by the day of the accident, the faceted layer was buried under 1½ to 2½ feet of settled snow.
Before the March 17 incident, the CAIC documented 19 human-triggered avalanches between March 1 and March 16 in the North San Juan forecast zone prior. The majority of those avalanches were triggered on northerly facing slopes above tree line and ranged from small to large.
In its summary, the CAIC commented that it hoped the report would “help people avoid future avalanche accidents.”
The snowboarder was traveling alone, which reduces resources for rescue if something goes wrong.
After taking two runs on sunnier, southwest-facing slopes, he moved toward cooler northerly terrain where the persistent slab was more dangerous.
Overton might have triggered the avalanche in a rocky area with a shallow snowpack, where the faceted layer was closer to the snow surface and an avalanche was easier to trigger. Avalanches on persistent weak layers are notoriously fickle and it can be challenging to assess slope stability.
The avalanche ran down where Overton had ascended and ran against adjacent terrain which created a terrain trap that caused a deep and dangerous burial.
There were no witnesses to the avalanche to call for help.
“Despite this good work from the Helitrax operation led to a fairly rapid response to this accident,” the CAIC report said. “Even with this rapid response, it took over an hour to excavate (Overton) from the avalanche debris.”
jmimiaga@the-journal.com
