Bulletin d’avalanche

Banff Yoho Kootenay

Dec 3 – 4, 2025Avalanche Canada
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Archivé · expiré 10 months ago

Danger d’avalanche

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

Points saillants

While winds have calmed, wind slabs remain in lee alpine and treeline pockets from Monday’s burst of westerly flow. Identify the loaded terrain and steer around it.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Monday had 24 hours of sustained W winds in the 40-60 km/hr range, and this subsequently ruined the soft snow down into treeline, and created widespread loading. Remain suspicious of wind loaded pockets.

Confidence

Moderate

Avalanche Summary

Sunshine reported triggering several size 1 hard wind slabs at treeline with explosives. Lake Louise also produced two size 2 avalanches in alpine lee features. They began as thinner wind slabs but then entrained mass by gouging down to ground as they ran.

Snowpack Summary

The previously soft surface snow has been erased with wind in alpine areas, creating windslabs. Some of this wind effect is down into the treeline, but mostly 20-40 cm of soft snow still remains at TL and below. Below ~2300 m, a rain crust exists below the storm snow. The mid- and lower-snowpack is well settled where thicker, and facetting where thin. Tree-line snow depths range from 60-100cm

Weather Summary

Slightly warmer than seasonal temperatures continue, with valley bottoms near –2°C and the ridge around –6°C. Cloud cover builds through Wednesday with light flurries. From Thursday into Friday, expect steady light snowfall, with total accumulations of 12–15 cm by Friday night. Winds increase through Wednesday, peaking near midnight with westerly gusts exceeding 60 km/h.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.

Régions couvertes