Bulletin d’avalanche

Purcells

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

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

We should see a rapid increase in temperatures early this week, resulting in a spike in avalanche danger. Check out the latest forecasters blog for advice on how to manage these changing conditions.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–4
    New wind slabs are likely in exposed lee and cross-loaded terrain from recent northerly winds. Old wind slabs lurk beneath, but triggering is less likely.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–5
    The 40 - 90 cm of storm snow has settled out nicely and the likelihood of triggering has greatly decreased. I suspect it's still possible to trigger an avalanche failing on the Jan. 4th interface in terrain that is steep rocky and/or convex.

Confidence

Good

Weather Forecast

Monday: A mix of sun and cloud. Freezing level is at valley bottom and alpine temperatures rise to -10. Winds are light from the north.  Tuesday: Mainly sunny with possible valley cloud. An above freezing layer will develop between 1200-1500 m. Winds are light to moderate from the north. Wednesday: Much the same as Tuesday - continued warm alpine temperatures and generally clear skies.

Avalanche Summary

The upper snowpack has tightened up with the cold temperatures and the time elapsed since the last storm. Overall numbers of avalanche observations have decreased, but the avalanches are getting more interesting/scary.  A group of skiers remotely triggered a size 2 avalanche from 70m away on a W facing aspect at TL Friday.  Explosive work in the region didn't produce much activity Friday. 

Snowpack Summary

40 - 90 cm of settled storm snow rests on the January 4th interface which consists of small facets, surface hoar (up to 12mm) in sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds at this interface are gaining strength but I still wouldn't bet the house on it. Recent tests on this interface show shears trending towards Resistant Planar. Professionals operating in the region are most concerned about slopes that have not yet avalanched. Wind slabs formed during the last storm are getting old and tired.The deep crust/facet combo from early November is till evident but it is inactive at this point. 

Régions couvertes