Bollettino valanghe

Northwest Coastal

Dec 20 – 21, 2012Avalanche Canada
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Archiviato · scaduto 14 years ago

Pericolo valanghe

Sat
Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–5
    A persistent weak layer of surface hoar, buried 60-80 cm below the surface has been reported from around Shames. Although triggering seems less likely, watch for convex rolls in sheltered areas where the SH may have been preserved.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–3
    Light amounts of new snow have been redistributed by strong winds into wind slabs on a variety of aspects. These wind slabs are adding to older storm snow accumulations which have most likely gained considerable strength.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    3–7
    Deeply buried weaknesses exist. Large triggers, such as cornice falls, could release deeper avalanches on steep, smooth terrain, especially in thinner snowpack areas.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Overnight Thursday and Friday: Light snowfall / Light to moderate southeast winds / Temperature inversion with ridgetop temperatures of -12.0Saturday: Mostly clear / Light southeast winds / Temperature inversion with ridgetop temperatures of -12.0Sunday: Trace amounts of snowfall / Light east winds / Ridgetop temperatures of -16.0

Avalanche Summary

Size 1 slabs have been reported from the south of the region, while slabs to size 2.5 were reported from steep alpine chutes in the Bear Pass area. All activity is suspected to have occurred within recent storm layers.

Snowpack Summary

Very light amounts of new snow have been redistributed by winds at higher elevations. This overlies the past week's storm snow which is settling rapidly, although weaknesses may still exist within storm snow interfaces. A buried surface hoar layer, reported to be 5 to 10mm thick, recently produced sudden snowpack test results down 60-80cm in the Shames backcountry, and may exist in other areas too. Avalanche professionals continue to monitor a faceted crust near the ground. It seems this problem is confined to alpine areas and likely needs a large trigger and/or a shallow snow pack feature to trigger. Cornices are also really big and forecast strong winds and cooling temperatures could make them especially heavy and brittle.

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