Thompson’s group was aware of the avalanche hazard for the day, which was listed as moderate by the Bridger-Teton Avalanche Center. They were adequately equipped for winter backcountry travel, wore helmets, and carried avalanche beacons, shovels, and probes.
Grand Teton National Park rangers, Jackson Hole Mountain Resort ski patrol, and the Teton County Search and Rescue helicopter coordinated a rescue effort for Alex Thompson, 26, of Jackson, Wyoming on Sunday, April 9 after he was caught in a soft slab avalanche in Granite Canyon.
Thompson was snowboarding in the park’s backcountry with three companions after exiting an open backcountry access gate at the Jackson Hole Mountain Resort ski area. Thompson was traversing across the top of Air Force Couloir when the slab broke above him. The sliding snow carried him approximately 1,000 feet downhill until he came to a rest atop the snow. Thompson suffered injuries during the fall due to collisions with rocks.
One of Thompson’s companions called Jackson Hole Mountain Resort ski patrol around 11:30 a.m. shortly after the slide. Ski patrol launched initial rescue efforts and called the Teton Interagency Dispatch Center as the incident was within park boundaries. Three ski patrollers skied down to Thompson’s location with a rescue toboggan and medical gear. They assessed Thompson’s condition and prepared him for ski-toboggan transport to the bottom of Granite Canyon and eventual aerial rescue.
Meanwhile, park rangers met the Teton County Search and Rescue helicopter and prepared to fly to the patient. With two park rangers on board, the helicopter landed near Thompson’s location and the rangers brought him aboard. Thompson was flown out to a temporary staging area along the Chapel of the Transfiguration road at 1:47 p.m., just as deteriorating weather conditions made visibility increasingly difficult. Thompson was transferred to a park ambulance and transported to St. John’s Medical Center in Jackson, Wyoming.
The avalanche crown left behind was six to twelve inches deep and measured 30 to 50 feet across. Rangers caution backcountry recreationists that recent snow squalls have deposited pockets of unstable snow at high elevations in the Tetons. Relatively small avalanches can still have serious consequences as they can carry victims long distances over terrain that can include trees, rocks, and cliff bands.