Bulletin d’avalanche

Cariboos

Mar 17 – 18, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Mon
Tue
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–5
    Recent southwest wind and new snow have developed windslabs in the alpine and at treeline. These windslabs may take a few days to settle and bond.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    3–7
    Persistent weaknesses are buried upwards of 150cm below the surface. Surprisingly large and destructive avalanches could be triggered naturally by the weight of additional snowfall, or by the energy of a person/sled.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–6
    The recent storm snow has consolidated into a cohesive slab. Extended sunny breaks may weaken the slab resulting in natural activity. Storm slab avalanches may step down to deeper weak layers.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

There are remnants of a system moving up from south of the border that may bring some moisture into the North Columbia mountains on Saturday night. Unsettled conditions are expected across the Interior regions again on Sunday. Some areas may see periods of heavy convective flurries, while others may see broken skies or scattered cloud. Winds should stay mostly light from the south, and the freezing level is expected to drop to the valley bottom Saturday night and then rise to about 800 metres on Sunday. Monday is forecast to be unsettled again, but with more likelihood of sunny periods. A Pacific frontal system is expected to start moving in from the coast on Tuesday bringing strong westerly winds and heavy precipitation.

Avalanche Summary

Avalanche activity continued on Friday with naturals reported up to size 2.5. Forecast sunshine over the next few days may cause another natural avalanche cycle.

Snowpack Summary

Periods of sunshine have caused moist snow on solar aspects up to about 1500 metres. Recent cornice growth has made cornices unstable. The new snow has added to the well consolidated storm slab that overlies weak surfaces that formed early February. This interface, which lies between 1 and 2 metres below the surface, includes a widespread surface hoar instability that, depending on aspect an elevation, may exist in combination with facets or crusts. These persistent weak layers have been reactive all week and remain a concern at all elevations. The weight of new snow, near-surface avalanches, sleds, and skiers may easily trigger these deeper weaknesses creating unexpectedly large and destructive avalanches.

Régions couvertes