Avalanche Forecast
Issued: Jan 3rd, 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.
JSmith,
Avalanche Canada
Recently formed storm slabs will be most reactive in wind affected areas at treeline and above. Be especially cautious as you transition into wind affected terrain.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
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SUNDAY NIGHT: Cloudy with flurries; 3-5 cm. / Strong, south ridgetop wind / alpine low temperature -9 / Freezing level valley bottom.
MONDAY: Snow; 5-10 cm, with another 5-10 cm overnight. / Strong, south ridgetop wind / alpine high temperature -5 / Freezing level 800 m.
TUESDAY: Mostly cloudy / Strong, southwest ridgetop wind / alpine high temperature -5 / Freezing level 800 m.
WEDNESDAY: Cloudy with flurries; 3-5 cm. / Strong, southwest ridgetop wind / alpine high temperature -3 / Freezing level 1300 m.
Avalanche Summary
On Sunday, numerous explosive triggered storm slab avalanches up to size 3.5 were reported just west of revelstoke.
On Saturday, numerous natural and skier triggered storm slabs to size 1 at treeline and below were reported.
Recently formed storm slab will be most reactive in wind affected terrain at treeline and above.
Snowpack Summary
15-25 cm of new snow brings recent snow totals to around 50 cm. Strong southwesterly winds, and mild temps have formed widespread storm slabs at all elevations.
Two persistent weak layers buried in early/mid Dec. are now 110-160 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. 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 lee and cross-loaded slopes at and above treeline.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Uncertainty is best managed through conservative terrain choices at this time.
Problems
Storm Slabs
New snow, strong winds and rising freezing levels have created widespread storm slabs ripe for human triggers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Smaller storm slabs in motion may step-down to deeper layers resulting in very large avalanches. This problem can be avoided through conservative terrain choices.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 4th, 2021 4:00PM
