Avalanche — Wasatch Mountains South of I-80, Utah

2024-05-09 · Wasatch Mountains South of I-80, Utah

Event narrative

A group of three backcountry skiers set out early in the morning to ski in the Big Willow Aprons area near Lone Peak. After skiing for several hours without issue, an unintentionally triggered soft slab avalanche occurred on the north aspect of the slope (approximately 40 degree angle) around 10,600 feet elevation. The avalanche was approximately 18 inches deep, 150 feet wide, and had a vertical run of 800 feet. All three skiers were caught by the avalanche. One skier was partially buried and was able to self-extricate. After self-extricating, the skier attempted to find the transceiver signal of the buried skiers. Approximately 13 minutes after the avalanche, the skier successfully probed one of the buried skiers and uncovered them, but they were ultimately unresponsive when rescue breaths were attempted. In the subsequent minutes, the second buried skier was probed and uncovered, but also found to be unresponsive to any resuscitation attempts. Around 1-1.5 hours after the avalanche, a helicopter ambulance was able to hoist the injured skier out, and this skier was subsequently taken to the hospital and released later in the day. Due to unfavorable weather, search and rescue recovered the deceased skiers bodies the following day.

Wider weather episode

A cold season type of trough and associated surface features moved through Utah in early May. Ahead of the system, strong synoptic wind gusts occurred throughout portions of the state. While wind gusts decreased following a cold frontal passage, precipitation increased. Periods of post-frontal precipitation then continued in the unsettled northwesterly flow as the trough shifted through the region. Given anomalously cold air associated with the trough, some area mountains received Winter Storm levels of snow, and sub-warning snow amounts were even observed in some lower elevation valley locations. Following the systems departure, a fatal avalanche occurred involving multiple backcountry skiers.

Source: NOAA Storm Events Database, event_id 1166963. Narrative written by the NWS forecast office that issued the report.