Avalanche Forecast

Issued: Jan 10th, 2021 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Persistent Slabs.

Avalanche Canada ahanna, Avalanche Canada

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A bit of new snow with strong wind will keep upper elevation wind slabs fresh on Monday. They will likely be thin but reactive, especially to human triggers.

Summary

Confidence

Moderate -

Weather Forecast

Sunday night: Flurries, up to 5 cm, moderate south wind, freezing level valley bottom.

Monday: Flurries, 5-10 cm, moderate to strong southwest wind, alpine high -6, freezing level 1200 m.

Tuesday: Flurries, up to 5 cm, moderate to strong southwest wind, alpine high -5, freezing level 1000 m.

Wednesday: Snow, 10-20 cm, moderate southwest wind, alpine high -5, freezing level 1200 m.

Avalanche Summary

A few reports of mostly minor solar triggered loose snow avalanches came in on Saturday afternoon. The occasional size 1 skier triggered wind slab is still being reported here and there.

Snowpack Summary

Small amounts of new snow fall on surface hoar in many areas and a thin crust on solar aspects. Previous moderate to strong winds have created variable wind effect at wind exposed elevations. 

A couple of persistent weak layers exist in the upper to mid snowpack:

  • The upper layer, found 50-80 cm down, is a spotty layer of surface hoar at treeline and below. 
  • The lower layer, found 90-150 cm down, is widespread and can present as surface hoar and/or a crust.

Avalanche activity on these layers has dwindled since last week and snowpack tests results have been moderate to hard planar, but still showing some propagation. Incoming snowfall in the forecast for this week will add additional load to these layers and may shed some light on whether they will remain a concern.

Terrain and Travel

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.

Problems

Wind Slabs

An icon showing Wind Slabs

Light snowfall with strong winds will likely form small wind slabs in lee and cross-loaded features at upper elevations.

Older, thicker wind slabs were very reactive before the weekend and may remain sensitive to human triggers.

Cornices have also been growing. A cornice fall is a large load that can trigger avalanches on the slope below.

Aspects: North, North East, East, West, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A couple of weak layers exist in the mid snowpack, buried 50-80 cm and 90-150 cm below the surface. They are highly variable in form and distribution and have not been associated with avalanche activity in recent days. Incoming snowfall in the forecast for this week will add additional load to these layers and may shed some light on whether they will remain a concern.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Jan 11th, 2021 4:00PM