Bulletin d’avalanche

South Coast

Jan 22 – 23, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré

Points saillants

Danger could be LOW below treeline in the Cascades where heavy rain saturated the snowpack and has probably refrozen into a solid crust.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    This problem may still be found in places that did not see widespread avalanche activity. Be particularly caution in the northern part of the region between 1500 and 1900 m elevation. 
  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Heavy snow continued in parts of the region on Friday helping create deep slabs at higher elevations, especially in immediate lee and cross-loaded terrain. 

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Saturday: Cloudy with sunny breaks. The freezing level is around 600 m and winds are light from the W-SW. Sunday: Cloudy with sunny breaks and a chance of flurries. The freezing level is at 500 m and winds are light from the S-SW. Monday: Cloudy with sunny breaks and a chance of flurries. The freezing level remains near 500 m and winds rise to moderate from the S-SW.

Avalanche Summary

Observations were quite limited during the storm on Thursday; however, a large and widespread avalanche cycle was very likely in most places. In the Coquihalla, a widespread cycle was observed with most avalanches being size 2-2.5 at treeline and in the alpine. At least one size 3 was reported with very impressive propagation. To the north (Upper Lillooet River), a widespread cycle was reported below treeline with avalanches up to size 2.5 being observed. I suspect we will hear more about this cycle in the next day or two.

Snowpack Summary

So far, 30-50 cm of new snow has fallen since Wednesday night. The snow line may have gone up to ridge top in the south, but only 1400-1600 m in the north. Expect dense new wind and storm slabs, and fresh cornice growth at upper elevations. Heavy loading from snow and rain, and the resulting avalanche cycle, may have flushed-out the mid- and early-January surface hoar/facet layers that were initially buried 30-50 cm deep. However, don't rule these layers out right away. It may still be possible to trigger shallow slopes that did not release naturally. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted.

Régions couvertes