Boletín de aludes

North Rockies

Mar 18 – 20, 2020Avalanche Canada
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Archivado · caducó 7 years ago

Peligro de aludes

Fri
Sat
Alta montaña
1 · Débil
Límite del bosque
1 · Débil
Bajo el límite
2 · Moderado

Lo esencial

Persistent slabs remain a concern at lower elevations. Observations will decrease as folks retreat to low-risk activities and social distancing. Be sure to keep risk tolerance to a minimum if you're heading out and to share your observations on the Mountain Information Network.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely - Possible
    Tamaño
    1–1.5

    Aging wind slabs exist on south, southwest, and west aspects. More recent slabs in steeper leeward features at ridgecrest may still react to the weight of a person or machine.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Previous storm snow has been settling into slabs over a persistent weak layer of surface hoar. Steep openings at lower elevations are the most likely areas to find and trigger this layer. While size is not expected to be large, be wary of terrain traps like tree wells or creeks and ravines where debris piles up deeply even from small slides.

Confidence

Moderate -

Weather Forecast

Wednesday night: Clear. Light east or northeast winds.

Thursday: Sunny. Light east or northeast winds. Alpine high temperatures around -8.

Friday: Sunny. Moderate west winds. Alpine high temperatures around -4.

Saturday: A mix of sun and cloud. Light north winds. Alpine high temperatures around -10.

Avalanche Summary

No new avalanches were reported over the past couple of days, however a natural wind slab avalanche cycle up to size 2.5 (large) was observed on Saturday. One size 3 (very large) was reported on a south aspect as well. No avalanches were reported at lower elevations where surface hoar is known to exist but where observations are scarce.

Looking forward, the possibility for human triggering of isolated wind slabs at upper elevations is now likely limited to very steep terrain at ridgecrest. At lower elevations, human triggering of avalanches remains possible where slabs have formed over persistent weak surface hoar layers.

Snowpack Summary

Recent sunshine has been strong enough to create a new surface crust on steep southerly slopes, thickest at lower elevations. Recent wind slabs are expected to be on a positive stabilizing trend.

At lower elevations, two surface hoar layers 50-60 cm and 75-90 cm below the surface remain a concern - especially where a slab has formed on the surface from warming and/or winds over the weekend. 

Terrain and Travel

  • Be very cautious in open terrain features, such as cutblocks, gullies, and cutbanks.
  • Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

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