Bulletin d’avalanche

Banff Yoho Kootenay

Nov 30 – Dec 1, 2024Avalanche Canada
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Archivé · expiré 2 years ago

Danger d’avalanche

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

Points saillants

Although we haven't seen the wind increase yet, they are still forecasted to increase to strong Friday night. This may create new windslabs and cause some loose dry avalanches.

The deep persistent problem remains the layer of greatest concern on large alpine slopes.

Problèmes avalancheux

  • Wind Slabs

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

    No significant wind occured on Friday, but it is still forecast to increase to strong Friday night through Saturday. If this occurs, we expect some windslab development in the lees of features.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    The crust/facet layer from October 23, located just above the ground, is capped by a 50-80 cm slab. This layer has caused avalanches over the past week. The extent of the problem remains uncertain, but we advise exercising extra caution on steep, open alpine features.

Confidence

Moderate

Avalanche Summary

Today, sunshine found thin windslabs in steep Northerly terrain that were reactive to explosives. Around Lake Louise, some loose dry avalanches were triggered by explosives in unworked terrain.

In the past week, we have seen several avalanches both natural and explosive triggered up to size 2 on the deep persistent layer. The common theme for these avalanches were North aspects in the alpine in steep or extreme terrain.

Snowpack Summary

10-20 cm of snow from last week lies on an early-season snowpack measuring 50-90 cm at treeline. The main layer of concern continues to be the October crust near the ground, where facets and depth hoar are developing. Overall the snowpack is losing its support/cohesion with facet development.

Weather Summary

Slightly warmer on Saturday with alpine temperatures around-10C. Westerly winds are forecast to increase to strong overnight Friday and into Saturday. Flurries are expected with the greatest amounts in the Northern part of the region (5-10 cm). See the image below for tables.

Terrain and Travel Advice

  • Be aware of the possibility for full depth avalanches due to deeply buried weak layers.
  • Avoid freshly wind-loaded terrain features.

Régions couvertes