Bulletin d’avalanche

Cariboos

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

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré

Points saillants

The new storm is expected during the day. Danger levels are expected to increase during the storm. These danger ratings may be a little high for the morning unless the storm comes early.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    The added load of new storm snow may allow for easy triggering of buried surface hoar where the snow above has settled into a cohesive slab.
  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    The new storm should develop during the day and avalanche danger is expected to increase. New snow may make it difficult to notice wind slabs left from the recent Northerly winds.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Overnight and Wednesday: A strong frontal system is expected to move into the region from the Northwest during the day and bring 15-20 cm by evening. Strong West-Northwest winds are expected during the storm and the temperature should rise, but the freezing level should remain at valley bottom.Thursday: Continued moderate precipitation bringing another 10-15 cm. Temperatures continue to rise slightly and moderate Westerly winds continue.Friday: Light precipitation and moderate Northwesterly winds.

Avalanche Summary

Expect increased sluffing of dry surface snow and near surface facets before the new storm snow arrives. The new storm snow may become easy to trigger where it is sitting on buried surface hoar and/or wind crusts.

Snowpack Summary

A new storm is forecast to add moderate new snow amounts above the dry cold surface snow that recently buried the very cold and facetted snow that was on the surface during the arctic outbreak. There is a great deal of variation in the snowpack with respect to elevation and exposure to winds. Shallow snowpack areas may be weak and facetted, and may not support the additional load of storm snow. The old storm snow (~30-50cm) overlies the late-November interface which typically consists of sun crusts on steep south facing slopes and surface hoar in sheltered areas. These weak layers are expected to be persistent, although in many areas the upper slab is not yet stiff enough for slab avalanches. When temperatures rise, and we get additional snow, expect this interface to become more reactive.

Régions couvertes