Bulletin d’avalanche

Northwest Coastal

Dec 3 – 4, 2017Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Warmer temperatures expected in the alpine with a strong temperature inversion by Wednesday. Avalanche hazard will likely increase during this time of change.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2
    Storm slabs may be reactive to rider triggers, especially at upper elevations where the storm snow has been affected by wind.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–4
    A lot of uncertainty exists around the reactivity of this layer near the base of the snowpack. A conservative approach to terrain is warranted while the snowpack adjusts to the recent load of storm snow and wind loading.

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Monday: Mostly cloudy with new snow 5-20 cm. Alpine temperatures near 0 degrees and freezing levels rising to 1400 m. Ridgetop winds strong from the west. Tuesday: Mix of sun and cloud. Alpine temperatures high of plus 3 and freezing levels 1600 m. Ridgetop winds moderate from the west.Wednesday: Sunny with valley cloud and alpine temperatures reaching a high of plus 9. Freezing levels 2000 m with a very strong alpine temperature inversion. Ridgetop winds moderate from the southwest.Expect strong inversions in the alpine up to 3000 m. For detailed information visit the Mountain Weather Forecast.

Avalanche Summary

On Sunday, dry loose avalanches were reported up to size 1. On Saturday, reports indicated several natural wind slab avalanches up to size 2 on northerly aspects in the alpine and dry loose avalanches from steeper terrain up to size 1 treeline and above. I remain suspect of the new snow and the bond to the buried crusts, especially the basal crust. I would be diligent and use a conservative approach to route selection while traveling through low consequence terrain, especially headed into the warmer weather forecast. Check out the Mountain Information Network for recently posted observations around the Shames area. Give info, get info.

Snowpack Summary

Recent accumulated storm snow amounts are from 100-130 cm and seem to be settling quickly with average snowpack depths 100-150 cm at treeline elevations. Deeper deposits of wind slab may be found on leeward slopes. This storm snow now sits above a 5-10 cm thick crust that was buried a week ago. Digging down 90-160 cm exists a crust/facet combo buried at the end of October. Recent snowpack test results are showing hard compression tests with sudden collapse results. I would keep this on my radar through the weekend to see how the snowpack adjusts to the new load.

Régions couvertes