Bulletin d’avalanche

South Columbia

Dec 13 – 14, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

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

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    3–5
    Forecast warming may increase the reactivity of an assortment of persistent weaknesses buried in the mid and upper snowpack. Triggering a persistent slab may have nasty consequences.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Forecast snowfall, wind and warming will add to a developing storm slab problem. Watch for increased reactivity in wind-affected terrain or at elevations where the upper snowpack has been affected by warming.

Avalanche Summary

In general observations in recent days have been limited due to weather; however, several soft wind slabs to size 1 were observed running in the lee of ridge crests on Thursday. With forecast wind, snowfall and warming I would expect ongoing slab avalanche activity throughout the weekend.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

Saturday: Moderate snowfall / Moderate to strong southwest winds / Freezing level at 1300mSunday: Light snowfall / Moderate to strong west winds / Freezing level at 1600mMonday: Light snowfall / Moderate southwest winds / Freezing level at 800m

Snowpack Summary

About 50cm of snow now overlies weak faceted crystals or small surface hoar that formed during the recent cold snap. On sheltered, lower elevation slopes the new snow is mostly unconsolidated; however, forecast warming and wind may enhance cohesion in snow surfaces creating a more reactive "upside-down" snowpack. Moderate to strong southwest winds have created wind slabs in exposed high elevation terrain.Professionals are still keeping their eye on the late-November interface which consists of hard sun crusts on steep south facing slopes and surface hoar in sheltered areas. This layer, buried between 40-70cm below the surface, has recently produced sudden test results and may be triggered with nasty consequences on steeper, unsupported terrain.At the base of the snowpack is a crust/facet combo that formed in October. About 60cm above the ground is a surface hoar layer which formed in early November. These layers have become generally inactive; however, residual risk of large, destructive avalanches exists, especially in areas with a thinner snowpack.

Régions couvertes