Bulletin d’avalanche

Northwest Inland

Apr 10 – 11, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Thin new wind slabs exist immediately lee of ridge crest and on cross loaded features.  Likelihood of triggering increases in steep terrain.  Massive cornices overhang many ridge lines and may fail without warning, even with the colder temps.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain on Friday

Weather Forecast

Synopsis:  A pacific low approaches the North Coast late Thursday bringing strong SW winds and widespread snowfall.  Thursday: Freezing Level: Valley bottom. Precip: Isolated convective flurries. Wind: Mod, WFriday: Freezing Level: Initially valley bottom, rising to 700m. Precip: 10/15mm – 10/20cm Wind: Strong, SWSaturday: Freezing Level: 800m Precip: Isolated convective flurries. Wind: Light, Variable.

Avalanche Summary

Wind loaded NW facing features produced size 1.0 loose snow avalanches on Tuesday.

Snowpack Summary

15-30 cm of new snow sits on a melt-freeze crust at most elevations. Warm temperature and a freezing level around 1000m during Tuesday night's storm combined with solar radiation resulted in moist snow on solar aspects at lower elevations. Pockets of wind slab have developed in exposed lee terrain and cross-loaded gullies. 30 - 60 cm of snow overlies a crust, old wind slabs or surface hoar layer buried on March 9th. The distribution of the surface hoar is also highly variable and it does not exist in every drainage. I would still remain cautious and continue to dig and test before diving into my line. Deeper in the snowpack, basal facets may resurface as a concern with continued mild temperatures.Cornices have become well-developed and could easily become unstable during periods of warm weather or direct solar radiation.

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