Item: West Twin Avalanche- Helicopter Involvement: How Safe are Our Pick-up Locations?
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Title: West Twin Avalanche- Helicopter Involvement: How Safe are Our Pick-up Locations?
Proceedings: International Snow Science Workshop 2014 Proceedings, Banff, Canada
Authors:
- Jeff Honig [ Selkirk Tangiers Heli Skiing, Revelstoke, BC, Canada ]
- Perry Bartelt [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Yves Bühler [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
Date: 2014-09-29
Abstract: On Feb 19 2014, a Bell 205 helicopter of Selkirk Tangiers Heli Skiing (STHS), was shut down at one of the most highly used pick-ups within their tenure East of Revelstoke, British Columbia. This landing site, located 60 vertical meters above the creek, was generally considered "safe" and commonly used during periods of high avalanche hazard. At 09:55, a size 3 avalanche released naturally on the steep rock face high across the valley. Even though the debris of the avalanche never reached the landing site, the helicopter was lifted into the air by the air blast, flipped mid-air, and dropped back onto the ground upside down 10 meters from the landing. The air blast also knocked down mature timber for 500 m down the valley. While nobody was seriously injured, this event raised a number of serious operational questions: What did our hazard evaluation miss that morning, or many other similar mornings when this spot was deemed safe? What kind of air blast speeds/forces are required to flip a 3200 kg helicopter? How many landings in our operation are threatened similarly? In this presentation, we apply a mixed flowing/powder avalanche model to numerically simulate this incident in detail and explore the impact of different scenarios on the safety at this landing site. We will then discuss the operational implications and make recommendations for improving the assessment of landing sites.
Object ID: ISSW14_paper_O14.04.pdf
Language of Article: English
Presenter(s):
Keywords: Avalanche, Helicopter, Heliskiing, Avalanche Modeling, Air Blast
Page Number(s): 394-401
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