Item: Cougar Corner - The Largest Snow Net Project in the Western Hemisphere
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Title: Cougar Corner - The Largest Snow Net Project in the Western Hemisphere
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Brian Gould [ Alpine Solutions Avalanche Services ]
- Cam Campbell [ Alpine Solutions Avalanche Services ]
- Andi Buechi [ Geobrugg AG ]
Date: 2018-10-07
Abstract: For over half a century, the Rogers Pass area in Glacier National Park, British Columbia has represented the epicenter of avalanche mitigation in Canada. Over 134 avalanche paths are known to affect the Trans-Canada highway, a major transportation route that winds its way through the pass. Since the early 1960s, avalanche protection for the highway has involved a mixture of snow sheds, diversion berms, retarding mounds, and an operational program that includes ongoing forecasting and artillery-based control using 105mm Howitzers operated by the Canadian Armed Forces. While the combination of these measures has functioned well, increasing traffic volumes and decreased tolerance for road delays has resulted in a need for new mitigation measures. One of these new measures is the Cougar Corner snow net system, which at almost 2 km in length, is the largest installation of snowpack supporting structures in the western hemisphere. Over two summers (2016 and 2017), this snow net system was installed in Cougar Corner 6, 7, and 8 - three steep avalanche paths involving a steep, complex, and rocky terrain. The design and layout of the system involved desktop terrain analysis using GIS, on site GPS survey, and numerous days of hands on measuring in complex terrain accessed via a combination of vertical ropes and via ferrata-type fixed traverse systems. Swiss-based design parameters were incorporated. Challenging terrain for snow net installation encountered during the layout process included sloping benches and incised gullies. Innovative solutions employed to overcome these challenges included the use of three debris flow barriers in a gully that was too incised to accommodate traditional snow nets. The site conditions during summer construction were complex and hazardous requiring the expertise of engineering consultants, mountain guides, drilling experts, as well as safety and helicopter logistics to complete the project. This abstract explores the design, layout, and installation of the Cougar Corner system and includes a summary of various methods and techniques that were incorporated. Challenges to the project that required innovative solutions are described. Feedback to date from two winters with above average snowpack height, indicate the snow net system is performing well.
Object ID: ISSW2018_O03.11.pdf
Language of Article: English
Presenter(s):
Keywords: snow avalanche engineering, mitigation, snow nets, debris flow nets, design.
Page Number(s): 256-260
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