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 - Uncertainty is due to the limited number of field observations.

Weather Forecast

Sunday night: Flurries, 5-10 cm, strong south wind, freezing level 1000 m.

Monday: Flurries, up to 5 cm, strong south wind, alpine high -5, freezing level 1300 m.

Tuesday: Flurries, up to 5 cm, strong southeast wind, alpine high -5, freezing level 1300 m.

Wednesday: Snow, 5-15 cm, strong southwest wind easing, alpine high -9, freezing level 1000 m.

Avalanche Summary

We have had a few recent reports of natural cornice falls and wind slab avalanches size 1-2 out of steep alpine terrain on north to east aspects

Field observations in this region are limited. If you get out, please consider submitting your observations to the Mountain Information Network. 

Snowpack Summary

Small amounts of new snow fall on surface hoar in many areas and a thin crust on solar aspects. Severely wind affected surfaces can be found at upper elevations, and in northern parts of the region, wind effect extends all the way down to treeline. Cornices have been growing large at ridgetop.

A couple of persistent weak layers exist in the upper to mid snowpack, down 20-60 cm and 70-100 cm. The distribution of these layers are variable, the upper layer spotty at treeline and below and the lower layer can present as surface hoar and/or a crust. It has been reported as most prevalent in areas near Valemount. Avalanche activity on these layers have dwindled since the storm and snowpack tests results have been moderate to hard planar, but still showing some propagation.

There is a prominent crust near the base of the snowpack. This crust likely has weak facets above and/or below it. There have been no recent avalanches reported on this layer, but would be most likely to trigger in steep, shallow, rocky terrain, where the snowpack transitions from thin to thick over a short distance.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Problems

Wind Slabs

An icon showing Wind Slabs

Light snowfall with strong winds will likely form small wind slabs in leeward terrain 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 20-60 cm and 70-100 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: Treeline, Below Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

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