Bulletin d’avalanche

Banff Yoho Kootenay

Jan 22 – 23, 2018Parks Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

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

Enjoy the new snow, but remember that there is enough whumphing and avalanche activity on the mid-pack weak layers to continue with a cautious approach to larger more committing terrain.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    Recent winds and snow have formed wind slabs in immediate lee areas and caused sluffing in steep rocky terrain. Pay attention to the surface texture and local wind transport patterns as these will be the biggest indicator of the wind slab problem.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5
    The Dec 15 surface hoar/facet layer continues to cause concern with forecasters. Only a few avalanche observations have been reported on this layer recently, but widespread cracking and whumphing is still occurring when traveling in the back country.

Weather Forecast

We should see some new snow Sunday night and into Monday with models showing between 5-10 cm of snow at treeline. Temperatures will remain below freezing with -10 to -12'C at upper elevations. 3000m winds will be moderate/strong SW Sunday night then dropping Monday. Tuesday sees a slight clearing trend and perhaps some more flurries on Wednesday.

Snowpack Summary

Newly formed wind slabs in immediate lee features at alpine and treeline elevations. In sheltered areas the upper snowpack consists of 20-30cm of soft slab over the Jan 6 surface hoar. The Dec 15 layer of surface hoar and facets is down 40-60 cm and is reactive in snow tests. Below treeline much of the snowpack is facetted with little structure.

Avalanche Summary

Two size 2 slabs triggered by wind loading and cornice failures were observed in the last 24 hours on Quartz Ridge and the 93 North. These both appeared to fail on a mid pack layer of facets. One skier triggered size 1 wind slab was reported in Semi Circular Bowl near Lake Louise. Numerous large sluffs out of steep rocky terrain in the last 36 hrs.

Confidence

Intensity of incoming weather systems is uncertain on Monday

Régions couvertes