Avalanche forecast

Northwest Inland

Jan 14 – 15, 2013Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Be aware of rapid warming already happening and forecasted solar radiation which will weaken the snow surface and possibly act as an avalanche trigger.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–5
    Be aware of rapid warming and solar radiation which will weaken the snow surface, possibly triggering an avalanche on the surface hoar layer down 80 cm or down to the deeper persistent weak layer from early November.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Monday night and Tuesday: A high pressure dominates the weather bringing clear skies in the alpine and valley clouds because of the inversion. Alpine temperatures should rise above or near near zero degrees and winds are forecasted to be strong from the West. Wednesday: The high pressure weakens allowing light precipitation. Freezing levels will be around 700 m. and moderate winds from the West.Thursday: Similar conditions expected with slightly more precipitation forecasted, strong West winds and warm temperatures.

Avalanche Summary

A few recent natural slab avalanches up to size 2 and a skier triggered avalanche size 1.5 were reported. The failure plane was the late December surface hoar.

Snowpack Summary

The surface hoar layer down 60-80 cm has started to be reactive in some areas with the warming.  There is also signs of intense wind effect in the alpine by recent strong NW winds leaving shallow areas and hard windslabs on lee side of ridges. The continuing warming and solar radiation forecasted for tomorrow will maintain the weakening of the snowpack trend. Read the forecaster's blog to learn more about this process. Triggering a surface instability could step down to the deeper persistent instability creating bigger avalanches. A strong mid-pack overlies a weak base layer of facets and the early November crust. Even though the crust has been unreactive for a while, professionals are concerned about it again with the warming which could awake it, especially in shallow areas at treeline and in the alpine.

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