Avalanche Forecast

Issued: Feb 21st, 2023 4:00PM

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

Avalanche Canada TT, Avalanche Canada

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Moderate to strong winds continue to redistribute the recent storm snow. Although, there has been a minimal natural avalanche activity observed following this weather change, wind slab and deep persistent slab are still of concern. Choose terrain conservatively and bear in mind the potential for a low probability high consequence avalanche occurrence.

Summary

Confidence

Moderate

Avalanche Summary

Parkway patrol on Tuesday observed minimal new natural activity. The visibility was intermittent but observations were made from all elevation bands and aspects. Significant wind drifting observed to reach to below tree line in wind prone areas.

Maligne road patrol on Tuesday saw no new natural avalanche activity.Late report from Shangrila area of a large avalanche off Mt Jeffrey reaching the creek likely on Feb 16.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Up to 15 cm of new snow from Monday night has been redistributed by the recent moderate to strong north to easterly winds. Reverse loading present in the alpine and open tree line. In sheltered locations the upper snowpack is comprised of 25-35 cm soft snow from the past couple of weeks on top of a generally weak mid and lower snowpack with facets and depth hoar at the base. The height of snow is variable from 50 to 150cm.

Weather Summary

Wednesday will be mainly cloudy with isolated flurries and trace of precipitation. Alpine temperature high is forecast at -28 C. Thursday brings a mix of sun and cloud, but the sun may only warm your soul and not your toes as the arctic air persists over the Rockies and alpine high is expected at - 26 C. Easterly lights wind shifting to southeasterly on Thursday.

Detailed weather forecasts from Avalanche Canada: https://www.avalanche.ca/weather/forecast

Terrain and Travel Advice

  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Problems

Wind Slabs

An icon showing Wind Slabs

With the new snow and a switch to northeasterly winds expect slab development on non typical lees. These wind slabs will have a potential to overload the deep persistent layer below and result in larger than expected avalanches.Strong winds affected open slopes below tree line. Isolated wind slabs may be present all the way to valley bottom on a smaller scale.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Natural avalanches continue to step down to this layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3

Valid until: Feb 22nd, 2023 4:00PM