Item: THE AVALANCHE IMPACT SCALE: A QUALITATIVE FRAMEWORK FOR FORECASTING AND RECORDING IMPACTS ON INFRASTRUCTURE, COMMUNITIES AND WORKSITE SAFETY
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Title: THE AVALANCHE IMPACT SCALE: A QUALITATIVE FRAMEWORK FOR FORECASTING AND RECORDING IMPACTS ON INFRASTRUCTURE, COMMUNITIES AND WORKSITE SAFETY
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Bree Stefanson [ BC Ministry of Transportation and Transit, Bear Pass Avalanche Program, Stewart, BC, Canada ]
- Ryan Boyle [ BC Ministry of Transportation and Transit, Bear Pass Avalanche Program, Stewart, BC, Canada ]
Date: 2026-09-28
Abstract: Effective risk management in avalanche-prone terrain requires a clear understanding of how avalanche activity interacts with specific elements at risk, such as worksites, infrastructure, and defence structures. This presentation introduces the Avalanche Impact Scale (AIS), a qualitative forecasting and recording tool designed to categorize potential and observed impacts on a six-level scale (0–5). The scale moves beyond traditional hazard ratings by directly linking avalanche impacts on operational outcomes and mitigation requirements. Levels range from Level 0 (No Risk), where activity is below the threshold for impact, to Level 5 (Historically Significant), representing catastrophic events that exceed engineered designs and require large-scale emergency responses like evacuations. Intermediate levels provide specific criteria for exposure controls and the impacts on avalanche defence structures. They also outline the implementation of safety measures such as training, Personal Protective Equipment (PPE), worksite signage, safe locations, closure points, and personnel sweeps. By utilizing this structured framework, avalanche practitioners can improve the consistency of risk communication, better manage vulnerability and exposure at worksites, and streamline the decision-making process for mitigation strategies. This presentation will detail the operational definitions of each level and discuss the practical application of the scale in protecting industrial and community assets. It is the opinion of the forecasting team in the Bear Pass Avalanche Program (BPAP) that forecasting for expected avalanche activity and recording avalanche occurrences based on this scale closes the forecasting feedback loop. This allows practitioners the ability to compare actual avalanche occurrences observed to their forecast and learn where they were correct or when it is time to reevaluate. Forecasting and recording this way can also help to train artificial intelligence, especially in programs that use automated devices such as avalanche radar detection. The BPAP has four seasons of forecasting and recording for each avalanche path utilizing the AIS with examples that can be used to showcase practical application of this scale.
Object ID: ISSW2026_O2.6.pdf
DOI: https://doi.org/10.15788/1790098560
Language of Article: English
Presenter(s): Bree Stefanson
Keywords: Forecasting, Recording, Communication, Risk, Management, Standardization
Page Number(s): 2398 - 2405
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