Avalanche forecast

South Columbia

Dec 16 – 17, 2021Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

 Use extra caution near ridgelines and "thick to thin" areas where the likelihood of triggering avalanches will be greater. The early December layer is starting to produce avalanches that could surprise experienced riders.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–2

    Isolated wind slab can still be found in exposed treeline and alpine features.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    30 to 80cm of snow sits on the early December facet crust combo. a few people have been surprised by this layer over the last week. Use extra caution around "thick to thin" slopes, especially in the upper treeline.

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

Wednesday night: No new snow expected. Wind will be light to moderate from the Southwest. Low of -11 at 1600m.

Thursday: Up to 5cm of new snow with a high of -8 at 1600m. Winds becoming strong from the Northwest in the alpine.

Friday: no new snow expected. Moderate winds from the Northwest shifting to the Southwest. High of -13 at 1600m.

Saturday: a storm arrives bringing up to 15cm of new snow with strong Southwest winds. High of -9 at 1600m.

Avalanche Summary

On Tuesday one skier triggered size 1.5 storm slab was reported on a North aspect at 2200m. This avalanche occurred on the facets above the early December crust. The slab was 35cm thick.

Snowpack Summary

Up to 20cm of low density snow overlies old wind effected surfaces.

The defining feature of the snowpack is a widespread crust that reaches as high as 2400 m and now sits 30-80 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. The faceting is most prominent in the upper treeline where the crust is thinner.

Average snowpack depth at treeline is 200cm.

Terrain and Travel

  • Be careful as you transition into wind affected terrain.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

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