Bulletin d’avalanche

South Columbia

Dec 18 – 19, 2015Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

The new snow may be hiding pockets of old wind slab on south aspects with fresh soft slabs developing in east facing lee features through the day.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Variable winds and an abundance of low density snow available for transport will continue to produce wind slabs in lee features. Look for shooting cracks as a sign you entering wind a wind loaded feature.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–4
    A layer of buried surface hoar can be found between 1400m and 1800m. Watch out for signs of instability like wumphing to guide you through this elevation band.

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

SATURDAY: flurries, moderate westerly winds, a warming trend with a high of -5C at tree-line. SUNDAY: light snow with accumulations of up to 10cm by the end of the day, moderate southerly winds, -5C at tree-line. MONDAY: flurries with accumulations of up to 5cm, light southerly winds, temperatures are forecast to fall to -10C at tree-line through the day.

Avalanche Summary

Avalanche professionals in the field were reporting sluffing in extreme terrain and isolated pockets of reactive wind slab.

Snowpack Summary

Up to 10cm of new snow on Friday combined with moderate southwest winds have formed fresh soft slabs in lee features in the alpine and at tree-line. The new snow may be sitting on a thin layer of surface hoar in sheltered areas at and below tree-line. Between 50 and 130cm of snow now sits on an extensive persistent week layer. The form of this layer varies depending on aspect and elevation: it can be found as a crust on south facing slopes in the alpine, or as large grained surface hoar and facets below tree-line. The surface hoar is most widespread in an elevation band between 1400m and 1800m. Snow pit tests suggest that human triggering of this interface is still possible, although unlikely, and that if it does fail the overlying slab is stiff enough to propagate the failure over a large distance. Below this the snowpack is thought to be mainly well settled.

Régions couvertes