Bulletin d’avalanche

Banff Yoho Kootenay

Jan 4 – 5, 2013Parks Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

The inversion is gone, but winds have picked up and are forecast to blow from the NW. This may raise the hazard in localized areas where there is still snow available for transport. Ice climbers pay attention to loading in the bowls above you!

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–2
    Moderate winds have created hard windslabs in exposed alpine terrain. Although these have not been reactive to human traffic, they may become more reactive as the alpine temps increase.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    The cold temperatures are facetting out cornices and large cornice failures have been observed. Currently there is an objective hazard from natural cornice failures as well as a hazard from human triggering while walking on ridges.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    This problem exists mainly in thin snowpack areas E of the divide where the snowpack has completely facetted and lost all cohesion. Watch for sloughing in steep terrain where the snow is unsupportive, particularly as temps increase.

Weather Forecast

The ridge is breaking down, bringing an end to the nice weather we've been experiencing, but giving hope of some new snow by Sunday!Fri: Alpine temps ~ -8. Alpine winds mod to strong NW. Overcast with trace accumulations.Sat.: Alpine temps ~-5. Alpine winds light to moderate W. Cloudy.Sun: Alpine temps ~ -10. Winds light SW. Up to 5 cm snow!

Snowpack Summary

Hard wind slabs exist in exposed alpine features but haven't been reactive to skier traffic. Suface hoar is growing in sheltered treeline locations. W of the divide, a well settled snowpack exists with the basal Nov 6 crust well bonded. In the front ranges E of the divide, a facetted snowpack exists with the Nov 6 basal crust being mainly facetted.

Avalanche Summary

A sunshine snow safety team member triggered a cornice while approaching the ridge to do cornice control.  The cornice dropped onto steep terrain, triggering a size 2 that failed on a recent wind slab layer.  Otherwise, no new avalanches.

Confidence

Régions couvertes