Bulletin d’avalanche

Northwest Coastal

Dec 23 – 24, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Exercise caution during the brief lu

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–5
    Strong west winds will keep loading lee feature.  While the peek period of natural activity may have passed it would be prudent to keep clear of overhead hazard and be aware that snowpack is primed for human triggering in many areas.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    3–6
    Give the problem layers deep in our snowpack some time to adjust to the new load.  There is the definite potential for very large step down avalanches.

Confidence

Poor - Timing of incoming weather systems is uncertain on Wednesday

Weather Forecast

Synopsis: A return to a drier, colder, northwesterly flow will occur tonight.  This is forecast to persist briefly until the next system hits the NW of the province.  This system resembles the last and is expected to once again hammer the region with heavy precipitation.Tonight and Tuesday: Expect scattered flurries overnight, becoming heavy snow by Tuesday evening as the next system hits.  The arrival of the cold front will keep freezing levels down around 600m.  Ridgetop winds will be moderate from the south west. Wednesday: Temperatures will rise as the warm front pushes onto the coast.  Freezing levels are expected to climb up to 1200m. The precipitation will be heavy in the morning but is expected to taper off later in the day. Winds will be strong from the west.Thursday: Periods of snow will persist through the day. Freezing levels are expected to remain high.  Winds will be strong from the southwest

Avalanche Summary

Numerous slabs up to size 3 reported during the last 48 hours.

Snowpack Summary

Yesterday brought another 30 to 40cm to the region.  The new snow settling rapidly due to the mild temperatures. We have no wind data from the region but given the expected strong to extreme winds we expect extensive wind slab formation in lee features.  Total pre-storm snowpack depths in the region vary between 150 - 250cm. On December 20th Kasiks (Between Terrace & Rupert) picked up almost 50cm while Bear Pass saw around 20cm. This snow rests on a variety of old surface layers down between 80-140cm: old wind slabs, a couple of crusts and surface hoar/facets that formed in early December.  The december week layers rests on stiff old wind slabs and melt freeze crust.  Below this The mid pack is composed of deteriorating layers of old facets and crusts. A significant basal facet and crust combo lingers near the ground and is most prevalent on NW - E facing aspects at the upper TL and alpine elevations.

Régions couvertes