Boletín de aludes

South Rockies

Feb 8 – 9, 2021Avalanche Canada
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Archivado · caducó 6 years ago

Peligro de aludes

Wed
Thu
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Lo esencial

Variable winds have mixed with recent snow, keep your head up for slabs in exposed terrain.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible - Likely
    Tamaño
    1–2

    Recent variable wind directions developed wind slabs on a variety of aspects. A weak interface may exist in some locations approximately 60 cm down and could reach its threshold with wind loading, initiating a deeper slab. At this point, this interface seems spotty through the region and hasn't been as reactive as in the Lizard-Flathead region. However, it is something to keep on your radar. 

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

SUNDAY NIGHT - Cold, cloudy with isolated flurries / alpine low temperature near -30 / light to moderate northwest wind

MONDAY - Cold, mix of sun and cloud / alpine high temperature near -22 / light northeast wind

TUESDAY - Still cold, but sunny / alpine high temperature near -20 / light northeast wind

WEDNESDAY - Cold with less sun and more cloud / alpine high temperature near -20 / light to moderate northwest wind

Avalanche Summary

Recent fresh snow has likely formed reactive wind slabs in wind loaded areas. Changing wind directions will mean that these wind loaded areas may potentially be found on any aspect.

On Friday there was a report of a size 2 explosives triggered wind slab avalanche, as well as a few size 1 human triggered dry loose avalanches. There was also a report of several natural avalanches, potentially up to size 3, a MIN report outlining these can be found here.

On Wednesday, numerous loose-dry natural avalanches were reported up to size 1. 

Snowpack Summary

Up to 45 cm of new snow fell over the past few days. The new snow was accompanied by strong winds, which redistributed snow to leeward slopes and terrain features forming fresh and reactive slabs. 

Up to 70 cm of recent new snow sits above a plethora of older snow surfaces. In the alpine and at treeline the buried interface consists of stiff, wind affected snow, facets, surface hoar in isolated areas sheltered by the wind, and a crust on steep solar aspects. Below 1900 m a thick crust can be found underneath the recent snow. 

A solid mid-pack sits above deeply buried decomposing crust and facet layers near the bottom of the snowpack (80-150 cm deep). Though unreactive under the current conditions, steep rocky slopes and shallow snowpacks should still be approached with caution.

Terrain and Travel

  • Avoid freshly wind loaded terrain features.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Avoid terrain traps where the consequence of any avalanche could be serious.
  • Be carefull with sluffing in steep terrain, especially above cliffs and terrain traps.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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