Bulletin d’avalanche

Kootenay Boundary

Nov 30 – Dec 1, 2011Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Due to shifting winds, wind slabs may be found on all aspects. If a weakness exists lower in the snowpack, a wind slab release may step down deeper producing larger avalanches.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Slabs have been developing over the past few storms. They seem to be settling out and becoming less of a problem.

Confidence

Fair - Due to limited field observations

Weather Forecast

A substantial upper ridge over the interior will bring dry, conditions under a cool northwesterly flow. Ridgetop winds on Thursday will be 30-40km/h from the northwest. Alpine temperatures will sit at -6 degrees, with the freezing level rising to 900m then dropping back to valley bottom at night. Friday through the weekend we can expect similar conditions with light-moderate winds in the alpine, and clear sunny skies.

Avalanche Summary

Up to 20cm of new snow fell over Tuesday night. With the clear sunny skies on Wednesday, the solar radiation kissed the southerly slopes producing size 1.0, loose moist avalanches. These were small and relatively harmless. I suspect we may see more of this during the sunny days to come. If you have any avalanche observations to report, please email us at: [email protected].

Snowpack Summary

Sunday's big system produced but a few centimeters of snow with freezing levels rising to 1800m, but winds were strong from the southwest forming wind slabs on lee slopes and terrain features. Generally there is about 150-200cm in the alpine, and treeline has been showing some variability between 50 -150cms. Recent snow pack observations are indicating the late October rain crust is present in the alpine elevations and down approximately 120cm. This crust is said to be up to 5mm in thickness with predominate faceting below it. For the moment the crust seems to be bridging over the facets below, with a settling, bonding snowpack above. There has been evidence of large avalanches running to ground in surrounding regions last Friday. I suspect this may have also occurred in areas of the Kootenay Boundary but have no solid reporting evidence. We should keep this layer in the back of our minds as we move forward.We hope to get some more information soon, as operators start getting out into the field. Any info from the field is welcome in our office. Let me know what you're seeing out there! [email protected]

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