Item: AVALANCHE FORECASTING FOR ICE CLIMBERS: ESTIMATING EXPOSURE AND MANAGING OPERATIONAL UNCERTAINTY
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Title: AVALANCHE FORECASTING FOR ICE CLIMBERS: ESTIMATING EXPOSURE AND MANAGING OPERATIONAL UNCERTAINTY
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Tim Ricci [ Yamnuska Mountain Adventures, Canmore, AB, Canada ]
Date: 2026-09-28
Abstract: Avalanche bulletins give us the regional picture, but ice-climbing decisions are made at one climb, one start zone, one runout, and often one short section of terrain. This paper looks at how Yamnuska Mountain Adventures (YMA) guides make that translation in day-to-day operations using End-of-Day Program Summaries and Daily Hazard Evaluations from calendar years 2023-2025. We identified 773 waterfall-ice guide-group records on 372 operating dates, representing 640 venue-days and 2,713 client participations. In a manually reviewed subset with standard five-level danger ratings, the Public Bulletin and YMA Localized Forecast agreed in 65 of 69 alpine pairs (94.2%), 70 of 71 treeline pairs (98.6%), and 63 of 68 below-treeline pairs (92.6%). We then applied practitioner estimates of typical avalanche exposure time to 707 records (91.5%). These records represent approximately 380 guide-group exposure hours and 1,180 person-exposure hours. The venues we used most were not necessarily where exposure accumulated: Junkyards accounted for 327 records but was assigned 0 h of routine sustained exposure under normal use, while Louise Falls accounted for 50 records and about 200 guide-group exposure hours. These estimates are not a risk score; they show where operational time in avalanche terrain accumulates. We describe the decision process as Hazard -> Uncertainty -> Terrain -> Exposure: start with the bulletin, identify what is uncertain, connect the problem to the terrain, then decide how much exposure to accept.
Object ID: ISSW2026_O8.2.pdf
DOI: https://doi.org/10.15788/1790098665
Language of Article: English
Presenter(s): Tim Ricci
Keywords: avalanche forecasting, ice climbing, spatial scale, uncertainty, exposure, operational risk
Page Number(s): 550 - 555
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