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Avalanche Forecast

Jan 10th, 2021–Jan 11th, 2021
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: North Columbia.

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.

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.

Avalanche Problems

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

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