Avalanche forecast

South Rockies

Jan 5 – 6, 2014Avalanche Canada
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Avalanche danger

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

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4
    Windslabs located under ridgetops mostly on E facing slopes will be sensitive to trigger by skier or sledder. Solar radiation and warmer temps in the alpine could make cornices fall which could trigger windslabs located under.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–6
    Depth hoar at base of snowpack and surface hoar or crust/facets combo layers down 100 cm could be triggered by a windslab avalanche or a sled airing onto a slope.

Confidence

Good

Weather Forecast

Tonight and Monday:The upper ridge still dominate the pattern leading to clear skies and possible valley cloud. Winds are forecasted to be moderate to strong from the NW. Freezing levels are at valley bottom but a weak above freezing layer (AFL) is warming temperatures between 2000 m. and 2800 m. Tuesday: A weak system could result in light precipitation with moderate winds from the NW. Freezing levels are at the surface and mainly cloudy skies.Wednesday: There is a slight chance of light precipitation coming from a Pacific frontal system. Strong Westerlies and freezing levels remaining at the surface.

Avalanche Summary

A natural avalanche cycle happened following the Friday's storm. Yesterday, avalanches up to size 2 were observed in the alpine and at treeline on all aspects. An avalanche size 2 would have ripped out in mellow terrain at treeline and is suspected to have run on a deep facet layer. Loose dry avalanches size 1 were also occurring in steep shady aspects and also on steep S aspects where surface of snow got moist at lower elevations.

Snowpack Summary

Winds that were forecasted yesterday did not effect the snowpack as much as expected, however there are pockets of windslab on E facing aspect slopes just below ridgetop in the alpine and top of treeline areas. Cornices also started building on the same aspect. In general, the storm snow is settling well in sheltered areas, the top dry snow is expected to keep sluffing in steep shady terrain and also on S aspects tomorrow as the sun and warm temperatures in the alpine weakens the surface. Cornices could also drop tomorrow with the warming of temperatures and sun shining on steep ridgetops. These could trigger pockets of windslabs that would be located under. The facet/crust layer down 80-100 cm at treeline and below treeline seems to be more active on E aspects. Yesterdays natural size 2 avalanche is a good reminder of that.

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