Boletín de aludes

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Feb 11 – 12, 2023Avalanche Canada
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Archivado · caducó 4 years ago

Peligro de aludes

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

Strong to extreme southwest winds will be on a wind slab building mission on Friday. Winds this powerful can build slabs surprisingly low in the terrain. Make observations on the extent of blowing snow and keep avoiding shallow, rocky areas where deep snowpack layers are more easily triggered.

Problemas de aludes

  • Wind Slabs

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

    Forecast strong to extreme southwest winds will ramp up wind redistribution of 20 cm of recent storm snow. Any snow still available for transport will feed into existing our existing wind slab problems, potentially forming new slabs quite low in the terrain. Approach all lee and cross-loaded terrain with caution.

    Keep in mind that wind slabs have the potential to step down to deeper weak layers, resulting in large and consequential avalanches.

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely - Possible
    Tamaño
    2–3.5

    A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure. See more on the potential of triggering deeper weak layers in our latest Forecasters' Blog.

Confidence

Low

Avalanche Summary

No new avalanches have been reported, but field information is very limited in this region.

We suspect users who head to the backcountry will see evidence of a natural wind slab avalanche cycle from recent storm snow and strong southwest winds.

Snowpack Summary

20-25 cm of snow from early this week is being redistributed by increasingly strong southwest winds into lee terrain in wind-exposed areas and at upper elevations. This overlies previous wind slabs and, a melt-freeze crust found on sun-exposed slopes and everywhere below 1600 m.

Several crust/facet/surface hoar layers exist in the upper and middle portions of the snowpack. The most concerning persistent weak layer is at the base of the snowpack from large and weak facets formed in November. This layer is widespread and most likely problematic in steep, rocky alpine terrain.

In general, the snowpack is weak and shallow in this area with an average snowpack depth of 100 cm at treeline.

Weather Summary

Friday night

Cloudy with isolated furries in the early morning. Strong to extreme southwest winds.

Saturday

Mainly cloudy with isolated flurries and trace accumulations. Strong to extreme southwest winds. Treeline high temperatures around -5.

Sunday

Cloudy with isolated flurries and trace accumulations. Strong to extreme southwest winds. Treeline high temperatures around 0 to +1 with freezing levels rising to 1800 metres.

Monday

Mainly cloudy with isolated flurries. Strong southwest winds easing to light west over the day. Treeline high temperatures around -5.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.

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