Bulletin d’avalanche

Banff Yoho Kootenay

Dec 3 – 4, 2022Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Human triggering of avalanches on the weak basal facets is still possible, and the thin early-season snowpack is hiding many hazards just below the snow surface. Use caution in steep terrain.

The cold temperatures will persist through Saturday, be prepared to stay warm in an emergency.

Problèmes avalancheux

  • Persistent Slabs

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

    Recent snow and wind loading has created slabs over a persistent weak layer of basal facets, buried sun crusts, or isolated pockets of surface hoar. This slab has been sensitive to natural and human triggering.

  • Loose Dry

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

    With the weak facetted nature of the snowpack, and increased winds expected through Saturday, wind transport could initiate dry loose avalanche activity in extreme terrain. Use caution in steep confined gullies where loose dry avalanches could have greater consequences.

Confidence

Moderate

Avalanche Summary

A number of wind-triggered loose dry avalanches up to size 1.5 were observed in steep alpine terrain on Friday. A few small wind slabs and several slabs on the basal facets up to size 2 have occurred in the past week.

Snowpack Summary

Some wind slabs building in the alpine with moderate to strong W/SW winds. 20-40 cm of recent snow sits over a very weak layer of facets, surface hoar, or sun crust on steep south aspects. 40-80 cm of total snow exists at treeline throughout the region, with up to 120 cm in loaded alpine features.

Weather Summary

The surface ridge persists over the Rockies on Saturday, with generally clear skies and cool temperatures. Treeline temperatures should moderate slightly to around -15°C by mid-day. Winds will be westerly in the moderate to strong range at the upper elevations.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • If triggered, loose dry avalanches may step down to deeper layers resulting in large avalanches.
  • Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.

Régions couvertes