Bulletin d’avalanche

Kootenay Boundary

Jan 31 – Feb 1, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

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

Storm slabs are settling and bonding, but the deeply buried  persistent weak layer continues to be a concern for human triggering.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–5
    This persistent weak layer is probably now best described as a low probability but high consequence problem. Dig down (80-120 cm) to see if the surface hoar exists in your area.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    The storm slab may continue to react to human triggers in isolated terrain where it is sitting on a buried surface hoar layer down 20-30 cm. The storm slab has not been reactive where it is bonding to a rain crust.

Weather Forecast

Freezing levels at or near valley bottoms for the forecast period. Overcast with flurries and light winds overnight. Overcast with light winds and a chance of flurries on Monday. Light winds with some sunny breaks on Tuesday. A system is forecast to move inland from the coast on Wednesday, expect increasing southwest winds, rising freezing levels, and light precipitation.

Confidence

High

Avalanche Summary

There were a couple of natural size 2.0 avalanches reported in the Rossland range that happened on Saturday. Some small natural wind slab or storm slab avalanches up to about 20 cm deep were reported on Saturday from the south of the region. On Friday a couple of operations reported natural slab avalanches up to size 2 that were releasing as pockets of wind slab or thin storm slab. Explosives controlled avalanches up to size 2.0 releasing in the storm snow were also reported on Friday. No new reports of any avalanches releasing down to the persistent weak layers.

Snowpack Summary

Most areas in the region had 3-5 cm of new snow on Sunday morning, the outlier was the southern Monashees in the west of the region where they had 26 cm of new snow overnight. The total recent storm slab of 20-30 cm (in most of the region) may be sitting on a layer of surface hoar that was buried on January 27th, or on top of one or two thin freezing rain crusts up to about 2100 metres. Some areas report that previous strong winds destroyed this new layer of surface hoar, and may have stripped the old surface back to a hard rain crust before the new storm snow arrived. The persistent weak layer that was buried January 4th is now down 80-120 cm and continues to give sudden planar fractures in snowpack tests in some areas.

Régions couvertes