Avalanche Forecast

Issued: Dec 14th, 2021 4:00PM

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

Avalanche Canada TRettie, Avalanche Canada

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Continually assess for wind loading as you change aspects. Up to 30cm of low density snow is availible for transport.

Summary

Confidence

Moderate -

Weather Forecast

Tuesday night: Alpine winds will be light from the Southwest with some light flurries bringing up to 5cm of new snow. A low of -10 at 1500m is expected.

Wednesday: alpine winds will be moderate from the Southwest. Some light flurries for the evening. High of -8 at 1500m.

Thursday: High of -8 at 1500m. Up to 10cm of new snow with winds becoming moderate from the Northwest.

Friday: High of -11 at 1500m. Moderate Northwest winds in the morning shifting to Southwest in the afternoon. No new snow expected.

Avalanche Summary

Two skier triggered wind slab avalanches were reported in the region on Monday. Both were size 1.5 in the treeline elevation. One was on a Southeast aspect and the other on a North aspect.

One skier controlled avalanche was also reported on Monday Near RMR. This was a size one wind slab on a North aspect at treeline.

Snowpack Summary

10 to 30cm of low density snow fell Tuesday morning with the largest amounts in the Selkirks. This overlies up to 30cm of old storm snow that was redistributed by moderate Southeast winds.

  

The defining feature of the snowpack is a widespread prominent crust that reaches as high as 2200 m in the alpine now sits 50-80 cm below the surface. In many places, overlying snow is well-bonded to the crust but in others weak faceted grains have been observed growing above it.

Average snowpack depth at treeline is 230cm.

Terrain and Travel

  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

Wind Slabs

An icon showing Wind Slabs

Skier triggerable wind slabs have still been observed on wind loaded slopes in the treeline and alpine.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

50-80 cm of snow sits over a weak layer on a thick crust. While only a handful of avalanches have been reported to have run on this layer, they have been large. Avalanches on this layer may be triggered by humans or vehicles from thin spots or by large loads like wind slab avalanches.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 15th, 2021 4:00PM