Boletín de aludes

South Rockies

Jan 29 – 30, 2022Avalanche Canada
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Archivado · caducó 5 years ago

Peligro de aludes

Mon
Tue
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Lo esencial

It may still be possible to trigger large avalanches on deeply buried weak layers. Be thoughtful with your terrain selection, especially around steep, rocky features.

Problemas de aludes

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely - Possible
    Tamaño
    2.5–3.5

    A concerning weak layer of faceted grains above a melt-freeze crust is around 100 to 150 cm deep, which has produced large avalanches. This problem has been less active recently, but we have been reminded multiple times in the last month that this layer could remain a concern all winter. Thin rocky start zones are the most likely place to trigger this layer. Snow loading from new snow and/or wind, daytime warming, cornice falls, and step-downs from smaller avalanches could increase the chance of an avalanche on this layer.

Confidence

High - We have a good understanding of the snowpack structure and confidence in the weather forecast

Weather Forecast

FRIDAY NIGHT: Clear skies with no precipitation, 40 km/h west wind, alpine temperature -8 C.

SATURDAY: Clear skies with no precipitation, 40 km/h west wind, alpine temperature -7 C.

SUNDAY: Increasing clouds with afternoon snowfall, accumulation 2 to 5 cm, 40 km/h southwest wind, alpine temperature -6 C.

MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm, 40 km/h west wind, alpine temperature -8 C.

Avalanche Summary

A few small wind slab avalanches were reported over the past few days, being triggered naturally or by explosives.

The last report of deep persistent slab avalanches are from Jan 21, when some very large avalanches were triggered by cornice falls and wind slab avalanches. Although deep persistent slab activity has recently tapered, it could still be possible to trigger large avalanches in steep, rocky terrain.

Snowpack Summary

Most areas are heavily wind affected. In the most sheltered areas, you may find surface hoar crystals on the surface. A melt-freeze crust may be found on steep sun-exposed slopes. 

The primary layer of concern in the snowpack is a crust that formed in early December and is now 100 to 150 cm deep. This layer is found most areas through the region, but with varying test results. Recently, the layer has shown more reactivity in shallow snowpack areas.

Terrain and Travel

  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
  • Carefully evaluate bigger terrain features on an individual basis before committing to them.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.

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