Bulletin d’avalanche

Kootenay Boundary

Dec 30 – 31, 2014Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

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

The Special Avalanche Warning has been extended until January 4th. Stay vigilant and be cautious in your terrain selection. Touchy persistent slabs exist and human triggering is likely.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Strong northerly winds has transported the recent snow into pockets of stiff reactive wind slab. Due to the reverse loading pattern, wind slabs may be triggered in unsuspecting locations in the alpine and at treeline.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–4
    A persistent weak layer, buried 30-80 cm below the surface continues to be a concern and skier/ rider triggering is likely.

Confidence

Fair - Wind effect is extremely variable

Weather Forecast

Arctic air is dominant and the weather remains benign with cold and mostly clear skies through Wednesday. High level moisture is developing on Thursday bringing some cloud cover. Alpine temperatures will be steady near -15 accompanied by moderate NW winds. On Friday things begin to change, however; at this point confidence is poor with model solutions and precipitation amounts.

Avalanche Summary

We continue to get reports of skier-triggered, and remotely triggered slab avalanches up to size 2.5. These avalanches are failing on all aspects from 1900-2300 m on a buried surface hoar layer 30-70 cm below the surface. This layer remains touchy to light loads, like YOU.

Snowpack Summary

Up to 35 cm of light, low density snow overlies recently formed surface hoar. Strong northerly winds have transported the new snow onto southerly aspects creating stiff and reactive wind slabs. Up to 80 cm below the surface, a touchy weak layer of surface hoar sitting on a thick rain crust exists. This widespread weak persistent layer consisting of surface hoar/ facets and a hard rain crust was buried mid-December and continues to produce whumpfing and sudden planar characteristics in snowpack tests. It will likely remain sensitive to human triggering for the foreseeable future. Although high elevation slopes may not have the rain crust, they are still reported to have touchy buried surface hoar. At the base of the snowpack, a crust/facet combo appears to have gone dormant for the time being.

Régions couvertes