Bulletin d’avalanche

Banff Yoho Kootenay

Dec 8 – 9, 2022Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

The basal facets aren't getting any smaller, and we have a more traditional snowpack than we have had in the past couple of winters. There are some fresh wind slabs, as well as weak facets near the ground. Treat any slope that has a wind slab overlying facets or crusts with caution as the potential for human triggering is higher.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–1.5

    5-25 cm of snow has fallen over the past few days and now will be blown into soft wind slabs. Watch for these on the immediate leeward side of ridges.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5

    A 20-60 cm slab sits over a persistent weak layer of basal facets, buried sun crusts, or isolated pockets of surface hoar. This layer has considerable uncertainty associated with it making it hard to forecast, and will be around for some time to come.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–1.5

    There is still a fair amount of loose snow sitting around on cliffs and ledges. If winds stay elevated on Friday, an avalanche will not be large but could collect in gullies with enough volume to knock a person over.

Confidence

Low

Avalanche Summary

One size 1.5 to 2 today in the Healy Creek area, failing on facets today. Lots of whumpfing in the Sunshine area overall, mainly on the facets. No other observations.

Snowpack Summary

5-25cm of snow and wind over the last few days has formed fresh wind slabs at higher elevations.

Here is an image of the typical snowpack in the Rockies; 81 cm snowpack at treeline at Crowfoot Glades. A few cm of low-density new snow on the surface, then about a 20-30 cm slab overlying the Nov 22 interface, below which facets and weak snow grains exist to ground. This snowpack is generally weak and will not handle much extra load.

Weather Summary

SW winds of 40-60 kph are expected overnight into Friday. Expected temperatures are -15C at ridgetop. On Friday, 20-40 kph winds are expected (some models showing higher values) with flurries and ridgetop temperatures ranging from -10C to -15C.

Régions couvertes