Avalanche Forecast
Issued: Dec 20th, 2019 4:02PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
Adam Greenberg,
Parks Canada
The storm rages on! Wet snow and rain will continue to load the snowpack on Friday night into Saturday. This continues to be a good time to avoid avalanche terrain.
Summary
Weather Forecast
Heavy wet snow or rain will continue Friday night and possibly Saturday with 110km/h winds and freezing levels near 2000m. There is some disagreement in the weather models on how much precipitation will arrive on Friday night and Saturday with amounts between 10 and 30cm, but the main event should be over by Sunday.
Snowpack Summary
30cm of wet snow and rain has arrived with extreme northwest winds and a freezing level around 1900m, providing a shock to the snowpack. A weak crust facet combo formed in November is down 60cm, and additional crust/facet layers formed in October form the bottom of the snowpack.
Avalanche Summary
No recent natural activity has been observed but visibility is poor. You can be sure slabs are building where the precipitation has come as snow.
Confidence
Intensity of incoming weather systems is uncertain
Problems
Storm Slabs
The atmospheric river continues to bring heavy snowfall accompanied by 120km/h southwest winds and rain below 1700m. Snowfall amounts are uncertain on Saturday, but winds will be strong and freezing levels will remain high.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Melt freeze crusts and facets from early season snowfalls are lurking at the bottom of the snowpack. This layer may come alive again with loading form the incoming storm.
- Good day to make conservative terrain choices.
- Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 23rd, 2019 4:00PM
