Banff Yoho & Kootenay National Park Avalanche Forecast

Issued: Nov 21st, 2021 4:00PM

Sun Nov 21st Current Conditions
Alpine Considerable Treeline Moderate Below Treeline Low
Mon Nov 22nd 2 Day Outlook
Alpine Considerable Treeline Moderate Below Treeline Low
Tue Nov 23rd 3 Day Outlook
Alpine Considerable Treeline Moderate Below Treeline Low

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

Good ski quality exists in sheltered areas near treeline. Although we didn't have any reports of large avalanches failing on the basal facets today, we have had several over the last week. This layer demands some respect and caution.

Summary

Weather Forecast

Monday looks to be clear with strong westerly alpine winds.  The winds die down Tuesday as the next storm approaches bringing 10 -20 cm with the highest amounts in the northern part of the region. Alpine winds will remain light to moderate from the west until Wednesday. Temperatures will stay cool in the -5 to -10 range at treeline elevations.

Snowpack Summary

5-20 cm of fresh snow in the last two days sits on a variety of surfaces: a rain crust below 2000m, a sun crust on steep solar aspects, windslabs in the alpine and exposed treeline areas and settled snow everywhere else. Melt/freeze crusts and/or facets lurk at the bottom of the snowpack. Snowpack depths at tree-line average 60-110 cm

Avalanche Summary

Fresh windslabs up to size 1.5 were reported from both Sunshine and Lake Louise ski hills. Today was the first day without a report of a deeper avalanche since last weeks storm, but there was limited observations due to visibility.

Confidence

Due to the number of field observations

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Reactive windslabs exist in the alpine and down into some tree-line locations. Wind loading was observed through the day Saturday and Sunday with moderate to strong west winds.

  • Use caution in lee areas. Recent wind loading have created wind slabs.
  • Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.

Aspects:

North, North East, East, South East, North West.

Elevations:

Alpine, Treeline.

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Possible - Unlikely

Expected Size

1.5 - 2.5

The lower snowpack is facetted on shaded aspects and a mix of facets and suncrusts on solar aspects. Although natural avalanche activity has decreased on this layer we continue to receive reports of human triggering.

  • Be wary of slopes that did not previously avalanche.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Valid until: Nov 22nd, 2021 4:00PM

Forecast Trend

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