Item: ASSESSING THE COLORADO AVALANCHE INFORMATION CENTER'S BACKCOUNTRY AVALANCHE FORECASTS
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Title: ASSESSING THE COLORADO AVALANCHE INFORMATION CENTER'S BACKCOUNTRY AVALANCHE FORECASTS
Proceedings: International Snow Science Workshop Proceedings 2023, Bend, Oregon
Authors:
- Spencer Logan [ Colorado Avalanche Information Center, Denver, CO, USA ]
- Ethan Greene [ Colorado Avalanche Information Center, Denver, CO, USA ]
Date: 2023-10-08
Abstract: Understanding the quality of a prediction is an integral part of improving any forecasting process. The Colorado Avalanche Information Center (CAIC) selected a set of public backcountry avalanche forecasts issued between November 2017 and April 2022 for verification. The forecasts came from continuous periods of one or more months and were from locations with a significant volume of observations. An individual assessor determined the avalanche danger and avalanche problems for a single day. Each assessor used the avalanche danger and problems from the day before their assigned period and a dataset of observations that included records from before and after each assessed day. Each assessment consisted of an avalanche danger rating for up to three elevation bands, up to three avalanche problems, a critical factor, and a confidence level. We calculated the avalanche activity index (AAI) for each day and location. Here we present the results of assessing three seasons and almost 1000 forecast days. The forecast and assessed avalanche danger rating matched 84% of the days, with a similar proportion of days where the assessment was higher or lower than the forecast. The difference between forecast and observed weather was the critical factor for many days when the assessment was lower than the forecast danger. The AAI was consistently and significantly higher on days when the assessed danger was higher than the forecast danger compared to days when the assessed danger matched or was lower than the forecast danger.
Object ID: ISSW2023_O5.02.pdf
Language of Article: English
Presenter(s): Spencer Logan
Keywords: forecasting, verification, avalanche danger
Page Number(s): 518 - 525
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