Item: QUANTIFYING THE RISK TO AVALANCHE PRONE ROADS: CONSIDERATIONS FOR IMPLEMENTING THE AVALANCHE HAZARD INDEX
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Title: QUANTIFYING THE RISK TO AVALANCHE PRONE ROADS: CONSIDERATIONS FOR IMPLEMENTING THE AVALANCHE HAZARD INDEX
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Jordy Hendrikx [ Antarctica New Zealand, Christchurch, New Zealand ] [ Department of Geosciences, UiT the Arctic University of Norway, Tromsø, Norway ] [ Dynamic Avalanche Consulting, Revelstoke, B.C., CAN ]
- Alan Jones [ Dynamic Avalanche Consulting, Revelstoke, B.C., CAN ]
- David Hamre [ David Hamre and Associates LLC, Anchorage, AK., USA ]
- Chris Wilbur [ Wilbur Engineering, Inc., Durango, CO., USA ]
Date: 2024-09-23
Abstract: The Avalanche Hazard Index (AHI) method was pioneered in the early 1980s and published by Schaerer in 1989. Since then, the AHI method has been applied to many North American and other international transportation corridors, including roads and railways. The AHI has been shown to be a useful tool for expressing risk, and for assisting in the planning of hazard mitigation. However, recent work in Alaska at a statewide level has demonstrated the importance of standardizing many of the key input parameters, if the intent is to provide direct comparisons between different avalanche management programs. Simultaneously, when using the AHI to optimally manage risk and prioritize mitigation measures for a single road, site specific calculations have the greatest value. This has been demonstrated to be especially useful for roads where the AHI is calculated over many years or even decades, whereby changes in hazard (or risk) can be tracked that result from either changes in traffic patterns, or in application of mitigation measures that reduce the risk. This paper provides an overview of the AHI method, and provides examples of where it has been used, and the sensitivity of the results to the selection of input parameters. It also presents solutions for addressing problematic aspects of the Schaerer (1989) formulation, including how to account for multiple lanes of traffic, highly variable traffic flows, variations in traffic composition, waiting traffic considerations, and a wider range of encounter consequences related to different types of avalanche flow. The aim of this work is to share the current state of knowledge in applying the AHI. This will aid our community in understanding the utilization of the AHI, and to promote a more deliberate and explicit application of this method that captures the key processes and decisions that are being addressed. Ultimately, this work will help provide a greater level of insight and transparency to the quantification of risk on avalanche prone roads, and clarity on how key parameters and assumptions impact the final estimate of risk in both an absolute and relative sense, when compared to prior and future AHI assessments.
Object ID: ISSW2024_O7.11.pdf
Language of Article: English
Presenter(s): Alan Jones
Keywords: Avalanche, Risk, Hazard, Management, Road, Railway, AHI
Page Number(s): 868 - 872
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