Bulletin d’avalanche

Banff Yoho Kootenay

Dec 19 – 20, 2022Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Buckle up, extreme cold is in the forecast. Natural activity has slowed, but be wary of steeper slopes where a slab overlies the facets. Where this condition exists, terrain choice will be the only way to reduce the uncertainty about whether a slope will slide.

Problèmes avalancheux

  • Deep Persistent Slabs

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

    A 20-60 cm slab has formed over the weak basal facets, with thin crusts at the interface on some solar slopes. We have not seen naturals in a few days, but human triggering is possible wherever a cohesive slab overlying these weaker layers exists. This problem will be around for a while.

Confidence

Moderate

Avalanche Summary

No new avalanche observations today.

Snowpack Summary

5-20cm of new snow over the past 2 days sits over a layer of recent surface hoar. At higher elevations, there is variable wind effect. The upper 20-60 cm of snow has formed a slab over the very weak base of facets and depth hoar. Snowpack depths at treeline range between 60 and 120 cm. Below treeline, the entire snowpack is weak and faceted.

Weather Summary

High pressure and -25C to -30C overnight into Monday AM with light E/NE winds and some flurries. Temperatures will continue to drop during the day with clearing skies. Monday night temperatures may get down to -35C or the coveted -40C.

Terrain and Travel Advice

  • Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
  • Uncertainty is best managed through conservative terrain choices at this time.

Régions couvertes