Bulletin d’avalanche

Banff Yoho Kootenay

Nov 20 – 21, 2015Parks Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

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

2 storms have formed most of the current snowpack, and its a very supportive snowpack considering its November. Watch for wind slabs in exposed terrain on high alpine slopes, especially where they may overly facets. Great ski conditions. SH

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    In thicker snowpack areas these have formed over previous storm snow and are less sensitive to triggering. In thinner zones these may be lying over weaker basal facets formed in the late fall, and where there was little snow before the last storm.

Weather Forecast

Alpine temperatures will stay in the -15 to -18C range for Friday, with mainly light N to NW winds and only trace amounts of snow. Temperatures will warm over the weekend with a slight temperature inversion , but still staying below freezing. Winds will also increase over the weekend as we switch to more of a westerly flow.

Snowpack Summary

A field trip to Kootenay today found 80cm of supportive snow at treeline, A profile at 2200m found a 1 finger snowpack under the latest storm snow, and rounded facets at the base. Exposed areas have wind slab development, and thinner alpine areas have a facetted base. This is consistent with other observations. Overall a good early season snowpack.

Avalanche Summary

Avalanche control yesterday produced results up to size 2.5, which were wind slabs. One size 3 was triggered on Mt. Stephen at 3000m which appeared to initiate near the ground. Many produced no result. There was a surprising lack of activity with extensive flights over the region, and little wind effect except in alpine regions.

Confidence

Due to the number of field observations on Friday

Régions couvertes