Item: ENHANCED WINTER PRECIPITATION NEAR FERNIE, BRITISH COLUMBIA
-
-
Title: ENHANCED WINTER PRECIPITATION NEAR FERNIE, BRITISH COLUMBIA
Proceedings: International Snow Science Workshop Proceedings 2023, Bend, Oregon
Authors:
- Michael Conlan [ Avalanche Canada, Revelstoke, BC, Canada ]
- James Floyer [ Avalanche Canada, Revelstoke, BC, Canada ]
Date: 2023-10-08
Abstract: The Lizard Range near Fernie, B.C. often receives high amounts of precipitation in winter months, which can be substantially more than forecast by weather models. In this paper we compare modelled precipitation amounts to measured amounts and analyze atmospheric trends to better understand scenarios that may lead to enhanced precipitation. The primary goal of the study was to better predict precipitation, which should lead to more representative avalanche forecasts for improved public safety. We obtained weather data between 2017 and 2023 and analyzed three weather models: the High Resolution Deterministic Prediction System (HRDPS), the Regional Deterministic Prediction System (RDPS), and the Global Deterministic Prediction System. We compared model data primarily to measurements at Fernie Alpine Resort (1615 m) but also to weather data from two neighbouring operations and to expected precipitation amounts recorded by avalanche forecasters. The most likely weather scenario for enhanced precipitation is having over 40 km/h southwest wind at 2000 to 3000 m elevation, often with a freezing level around 1000 to 1500 m, accompanied by a coastal low pressure system and frontal passage over the Lizard Range. High snow-to-liquid ratios may occur when the minimum air temperature at around 1600 m is 5 °C or colder. Models may properly predict or over-predict QPF when the 2000 m and 3000 m wind are below 40 km/h, particularly for the HRDPS. Forecasters can use these findings to better forecast winter precipitation near Fernie.
Object ID: ISSW2023_P1.06.pdf
Language of Article: English
Presenter(s): Michael Conlan
Keywords: enhanced precipitation, Fernie Factor, numerical weather prediction, weather forecasting, avalanche forecasting
Page Number(s): 173 - 178
-