Avalanche forecast

South Columbia

Dec 29 – 30, 2013Avalanche Canada
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Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    New snow combined with moderate to strong southwest and northwest winds have created wind slabs in the lee of terrain features on a variety of aspects. 

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–5
    Buried persistent weak layers exist in the upper 110 cm of the snowpack.

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Monday: Light to moderate snowfall, alpine temperatures -3, freezing level at 1200m, winds moderate to strong from the west.Tuesday: Mainly cloudy with isolated flurries. Alpine temperatures -5 and freezing level at 1200m. Winds light to moderate from the west.Wednesday: Mainly dry with broken skies, alpine temperatures -6 with light winds from the west.

Avalanche Summary

A few slab and loose avalanches to size 1.5 have been reported in the last 2 days. These are isolated to the most recent storm snow.

Snowpack Summary

Recent moderate to strong southwesterly and northwesterly winds continue to build wind slabs in alpine and treeline lees. 30-50 cm of storm snow sits on a weak layer consisting of surface hoar crystals, stellar crystals and/or crust. Around 60-90 cm below the snow surface, the early December surface hoar, facetted snow, and/or a crust interface sits and is reportedly still variably reactive in snowpack tests.The late-November persistent weak layer consists of a sun crust on steep south facing slopes and surface hoar in sheltered areas. It is now buried 80-110cm below the surface. Snowpack tests vary on this interface with some results producing "sudden" shears and others producing no results. This interface is generally considered to be dormant. However, professional operators are still keeping a close eye on it.A weak layer of facets sitting on a crust that formed in October, sits near the base of the snowpack. This layer is predominantly found on north-facing alpine slopes with smooth ground cover. Triggering this weakness is unlikely, however if triggered the resulting avalanche would potentially be a large event with high consequences.

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