Item: AN ANALYSIS OF FORECASTER ACCURACY IN PREDICTING AVALANCHE PROBLEM TYPE AND LIKELIHOOD IN SKI AREA OPERATIONAL HAZARD ASSESSMENTS
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Title: AN ANALYSIS OF FORECASTER ACCURACY IN PREDICTING AVALANCHE PROBLEM TYPE AND LIKELIHOOD IN SKI AREA OPERATIONAL HAZARD ASSESSMENTS
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Wendolyn Antibus [ Mt Rose Ski Tahoe ] [ American Institute for Avalanche Research and Education ]
- Evan Leonard [ Mt Rose Ski Tahoe ]
- Matt Zupan [ Mt Rose Ski Tahoe ]
Date: 2024-09-23
Abstract: Forecasting staff at Mt Rose Ski Tahoe have been utilizing the InfoEx International product to issue daily hazard assessments and record avalanche activity within ski resort terrain since 2019. In order to improve our forecasting process, we reviewed the past four seasons data to determine if operational AM Hazard Assessments were providing an accurate representation of observed conditions. Our aim was not only to quantify forecast accuracy, but to identify any steps within the Conceptual Model of Avalanche Hazard (CMAH) based process that were prone to error. Utilizing hazard assessment and avalanche observation data recorded in InfoEx, we compared avalanche problem type, distribution, and sensitivity on AM and PM operational hazard assessment forms to determine the frequency which forecast avalanche problem, sensitivity, distribution, and likelihood differed from observed problems. We also analyzed days when widespread natural avalanche activity and remote triggering were observed to evaluate whether conditions were accurately described in the morning assessment. Comparing AM with PM Hazard Assessments, adjustments were made to the avalanche problem type in 4% of total forecasts and sensitivity rating 13% of the time. A retrospective look at AM forecasts compared to results from avalanche mitigation work appears to demonstrate a tendency to describe more avalanche problems within the AM hazard assessment than are observed during the subsequent day. Major cycles of natural avalanche activity were well captured in the AM assessment, however, natural releases involving persistent slab problems were sometimes not anticipated. Use of a CMAH based workflow process appears to provide an accurate method to anticipate hazard conditions within ski resort terrain. Ski resort operational data provides a robust data set for evaluating hazard assessment, as routine slope testing with explosives for operational objectives provides immediate feedback on forecast accuracy.
Object ID: ISSW2024_O1.11.pdf
Language of Article: English
Presenter(s): Wendolyn Antibus
Keywords: Avalanche Forecasting, Ski Resort Operations, Conceptual Model, InfoEx, Avalanche Problem Type, Avalanche Likelihood
Page Number(s): 65 - 69
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