Avalanche Forecast
Issued: Jan 5th, 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
Lots of recent fresh snow, strong southwest winds, and a buried weak layer means that human triggered avalanches remain likely for now. Choose conservative terrain.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
TUESDAY NIGHT - Cloudy with flurries, 5-10 cm / strong southwest wind / alpine low temperature near -7Â
WEDNESDAY - Mainly cloudy with a few flurries, 5-10 cm / moderate southwest wind / alpine high temperature near -5 / freezing level 1400 m
THURSDAY - A mix of sun and cloud / light northeast wind / alpine high temperature near -7Â
FRIDAY - Mainly sunny / light southeast wind / alpine high temperature near -2
Avalanche Summary
Recent storm slabs will likely be easiest to trigger in wind loaded areas, as well as in the trees where they may rest on a buried surface hoar layer.
Numerous size 1-2 human and explosives triggered storm and wind slab avalanches were reported on Monday.Â
It is notable that there were several human triggered avalanches reported at lower elevations in the neighboring Glacier National Park region on Monday. These avalanches highlight the potential to trigger avalanches in the trees. Reports of these can be viewed here, here, and here.
On Sunday, numerous natural, human and explosive triggered storm slab avalanches up to size 3.5 were reported in the region. Check out this MIN report from Sunday of an avalanche below treeline on Begbie Shoulder.
On Saturday, numerous natural and human triggered storm slabs to size 1 at treeline and below were reported.
Snowpack Summary
20-40 cm of recent fresh snow brings storm snow totals to around 40-80 cm. Strong southwest winds overnight have likely formed widespread storm slabs. In many areas, the storm snow sits on a weak layer of surface hoar that was buried around Christmas. This layer continues to be of concern, mainly at treeline and below treeline.
Two persistent weak layers buried in early/mid-December are now down about 90-150 cm. The form and distribution of these layers are highly variable and may 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. This layer also remains a concern, primarily at treeline and below.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
- 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 and recent strong winds have created storm slabs that will likely still be easy to trigger, especially in wind loaded areas and at lower elevations where they may sit on a buried weak layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Two persistent weak layers buried in early/mid-December are now down 90 to 150 cm. The form and distribution of these layers are highly variable and have may vary significantly from one valley to the next, and between elevation bands.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 6th, 2021 4:00PM
