Avalanche Forecast
Issued: Jan 4th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
Storm slabs will likely be reactive to human triggering, especially in wind loaded areas. Watch for signs of instability such as whumpfing, cracking and recent avalanches.
Concern remains for persistent weak layers, which are best managed through conservative terrain choices.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
MONDAY NIGHT - Flurries, around 10 cm / light to moderate southwest wind / alpine low temperature near -10Â
TUESDAY - Mainly cloudy with a few flurries / light south wind becoming moderate southwest in the afternoon / alpine high temperature near -7Â
WEDNESDAY - Mainly cloudy with a few flurries, up to 5 cm / moderate southwest wind, easing in the afternoon / alpine high temperature near -6 / freezing level 1300 m
THURSDAY - A mix of sun and cloud / light northeast wind / alpine high temperature near -5Â
Avalanche Summary
On Sunday, numerous explosive triggered storm slab avalanches up to size 3.5 were reported just west of Revelstoke.
On Saturday, a skier triggered a size 2 slab avalanche near the Gorge area. See the excellent MIN report here.
Recently formed storm slab will be most reactive in wind affected terrain at treeline and above.
Snowpack Summary
10-20 cm of new snow brings recent storm snow totals to around 50-70 cm. Recent strong southwesterly winds have formed widespread storm slabs at all elevations.
Two persistent weak layers buried in early/mid-December are now 110-180 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can differ significantly from one valley to the next. The first layer has been primarily reported as small surface hoar. The next layer has been reported as a thin freezing rain crust, surface hoar, or thick rain crust depending on elevation and location. As a result, diligent investigation of the snowpack is required to get a handle on local conditions.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Uncertainty is best managed through conservative terrain choices at this time.
Problems
Storm Slabs
New snow and recent strong winds have created widespread storm slabs that are still likely to be triggered by humans in many areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Two persistent weak layers buried in early/mid-December are now 100 to 180 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can vary significantly from one valley to the next.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 5th, 2021 4:00PM
