Item: CHARACTERISTICS OF INBOUNDS AVALANCHE FATALITIES AT UNITED STATES SKI AREAS
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Title: CHARACTERISTICS OF INBOUNDS AVALANCHE FATALITIES AT UNITED STATES SKI AREAS
Proceedings: International Snow Science Workshop Proceedings 2023, Bend, Oregon
Authors:
- Paul Baugher [ Northwest Avalanche Institute, Crystal Mountain, WA, USA ]
- Scott Savage [ USDA Forest Service Sawtooth Avalanche Center, Ketchum, ID, USA ]
- Karl W. Birkeland [ USDA Forest Service National Avalanche Center, Bozeman, MT, USA ] [ Friends of the Colorado Avalanche Information Center, Evergreen, CO, USA ]
Date: 2023-10-08
Abstract: Inbounds avalanche fatalities are both tragic and rare. Largely due to the diligent mitigation efforts of avalanche programs, the risk of a skier or snowboarder dying in an avalanche at a U.S. ski area is roughly less than one death per 60 million skier visits. Despite this exemplary safety record, the inbounds avalanche risk is not zero and cannot be completely eliminated. During the past two decades, an average of about one public avalanche fatality per season occurred within the boundaries of a U.S. ski area. A total of 17 people were killed in 14 avalanches. We analyzed these accidents and found that many of them: 1) occurred when opening terrain for the first time that season, 2) involved post-mitigation release avalanches (PMRs), 3) fractured on persistent weak layers, and 4) occurred with multiple people on the slope. Our findings are consistent with past research on PMRs dating back to 1978. Previous papers present several hypotheses for the cause of PMRs, but recent avalanche release research better informs our understanding of these events. Avalanches require initiating a critical weak layer crack that propagates across the slope before it releases. Due to the spatial variability of slabs and weak layers, sometimes an avalanche path may contain only a few potential trigger spots. Locating those spots can be challenging, and public skiers may find these spots and trigger a PMR. A thin margin for error exists when opening avalanche-prone ski area terrain, especially for the first time of the season. This paper aims to improve understanding of recent fatal inbounds avalanches, thereby helping ski area personnel further reduce PMRs and inbounds avalanche fatalities.
Object ID: ISSW2023_O14.05.pdf
Language of Article: English
Presenter(s): Paul Baugher
Keywords: inbounds avalanches, post mitigation release, ski area risk management, avalanche mitigation, ski area avalanche fatalities, ski area litigation
Page Number(s): 1207 - 1213
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