Avalanche forecast

Northwest Inland

Dec 24 – 25, 2011Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Wind slabs have developed on lee and cross-loaded terrain in the alpine and at treeline. Rider triggered wind slabs are possible.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Persistent slabs have now formed at all elevations where the mid December buried surface hoar/crust/facet layers exist. Reactivity has probably decreased somewhat, but the consequence of an avalanche remains high.

Confidence

Fair - Intensity of incoming weather is uncertainfor the entire period

Weather Forecast

Sunday: Trace amounts of snow - Freezing level at 500m - moderate westerly windsMonday: 10-15cm of snow - Freezing level at 400m - moderate to strong southwest windsTuesday: light to moderate snowfall - Freezing level at surface - light to moderate southwest winds

Avalanche Summary

No new avalanches have been reported. Any information (professional or recreational) from the field is highly appreciated. Please send your observations to [email protected].

Snowpack Summary

Over the past week the Hankin/ Hudson Bay Mtn area received up to 30cms of new snow accompanied by strong southwest winds. Storm slabs and wind slabs have formed. There is now around 55cms of snow sitting on a surface hoar/crust/facet combo which is the result of the early December dry spell. This crust is widespread and exists in most start zones up to 2000m. Facets can reportedly be found above or below the crust. Prior to being buried, the surface hoar was destroyed by high winds in the alpine, but still coexists with the crust at treeline and below. What is the tipping point of this weak interface? In areas where this interface has reached its threshold, natural and human triggered avalanches up to size 2.5 have occurred. If they have yet to happen, I suspect they are gaining some strength but would still react to a rider trigger, especially in steeper, unsupported terrain features. In short, the upper snowpack is variable and deserves caution. It will also see increased load with forecast wind and snow.Beneath this the midpack is well settled and strong.The base sits at about 115cm at treeline and about 135cm in the alpine.

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