Item: MISSION-FOCUSED RISK MAPPING FOR AVALANCHE CONTROL IN GLACIER NATIONAL PARK
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Title: MISSION-FOCUSED RISK MAPPING FOR AVALANCHE CONTROL IN GLACIER NATIONAL PARK
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Chris Argue [ Dynamic Avalanche Consulting Ltd., Revelstoke, BC, Canada ]
- Danyelle Magnan [ Parks Canada, Revelstoke, BC, Canada ]
Date: 2026-09-28
Abstract: Avalanche control for the Trans-Canada Highway (TCH) and Canadian Pacific Kansas City Railway through Rogers Pass in Glacier National Park (GNP) relies on an extensive artillery program using 105 mm howitzers fired from roadside positions, delivered via a partnership between Parks Canada and the Canadian Armed Forces. During control missions, a Parks Canada Mountain Safety Team (MST) forecaster directs artillery fire and observes results from a vehicle on the closed highway, sometimes adjacent to or within the target avalanche path. Since 2011, there have been two incidents where artillery-controlled avalanches have impacted and buried an MST vehicle, fortunately without serious injuries. Following the most recent incident, Parks Canada requested linear risk mapping to better manage exposure during control missions. This paper summarizes methods used to develop risk mapping for the TCH corridor and gun positions to support MST risk management decisions, and the resulting benefits during operational use. Quantitative risk was classified into four classes based on suggested natural-hazard thresholds in Canada and assigned corresponding risk ratings. Mapping was based on 60 years of avalanche occurrence records to estimate avalanche probability, together with field observations collected at a minimum of 50 m intervals along the highway. Worker vulnerability considered entrained timber and the consequences of steep terrain below the roadway. Results are presented independently for the north and south sides of the valley, allowing the MST forecaster to adjust their position once one side has been controlled. The mapping is paired with an internally developed avalanche control Risk Level Framework (RLF), which is used to evaluate mission risk for avalanche control operations based on team factors, environmental conditions, and expected avalanche character. Each risk class includes guidance linked to the RLF to support MST forecaster positioning during control operations. The risk mapping has been used operationally over the past two winters. Key benefits include reduced reliance on visual landmarks and informal heuristics to identify "safe" observation locations, and a more objective basis for managing exposure, particularly during low visibility and nighttime operations.
Object ID: ISSW2026_P2.16.pdf
DOI: https://doi.org/10.15788/1790098917
Language of Article: English
Presenter(s): Chris Argue
Keywords: Risk, artillery, avalanche, control, mapping.
Page Number(s): 522 - 528
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