Snowmobiler dies of injuries after triggering avalanche in Idaho mountains

The Sawtooth Avalanche Center said a snowmobiler was killed Friday in an avalanche in the Smiley Creek drainage, about 8 miles southwest of the Galena Summit in the Boulder mountains between Stanley and Ketchum.

The SAC’s Instagram page reported one member of a large group was “highmarking” — riding up a steep slope from the bottom — on a south-facing slope near 9,000 feet in elevation.

The upper portion of the slope was wind-loaded. The rider triggered a very large avalanche approximately 500 feet wide and 3 to 4 feet thick, which ran over 1,000 vertical feet. The rider was caught and carried into trees near the bottom of the slide path.

The man deployed his avalanche airbag and was not buried under the snow but sustained severe injuries. Members of the rider’s party were unable to revive the rider at the accident site. He has not yet been identified publicly.

“We extend our heartfelt condolences to the victim’s friends and family,” the Sawtooth Avalanche Center’s Facebook page said.

U.S. Forest Service Sawtooth Avalanche Center staff visited the site and will release additional information and an incident report in the coming days.

“Thursday night’s new snow and wind likely built a round of small, fresh drifts and sensitive cornices,” The agency’s Friday avalanche forecast said. “These hazards may be dangerous on their own, but can also act as triggers for larger avalanches that fail on weak snow buried 2-3 feet deep. You can reduce your risk by steering clear of steep slopes with drifts or stiff snow near the surface.”

“Our area is known for its weak layers,” avalanche specialist Chris Lundy said. “We haven’t seen this weak of a layer in years, one as persistent as this one is about every 10 years, and it can be problematic for the entire state, not just our area.”

The Sawtooth Avalanche Center said that since winter 2003-04, eight snowmobilers have died in avalanches in Idaho — a more than two-to-one ratio compared to all other user groups.

“The Galena Summit area is the most popular for skiers and the Baker Creek drainage is popular with snowmobilers,” Lundy said.

The four zones in and around the Wood River Valley all remain in either the moderate- or considerable-rating ranges for avalanche danger.

This story was originally published February 21, 2021 at 2:15 PM.