Bulletin d’avalanche

South Rockies

Dec 10 – 11, 2011Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
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
    Taille
    1–3
    Windslabs are settling and becoming less & less of an issue in the region. Never the less, you'll need to stay heads up and watch for wind slabs on the immediate lee of features in the Alpine.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    With numerous recent avalanches failing on this layer in adjacent regions, the potential for large, destructive & likely unsurvivable full depth avalanches remains a concern for backcountry travelers this weekend.

Confidence

Fair - Due to variable snopack conditions

Weather Forecast

Sunday looks to be a pretty mild weather day. Winds will be light out of the E-NE, freezing levels remain at valley bottom and temperatures stay steady at -7. A weak ridge builds back into the area Monday before breaking down Tuesday allowing another mild system to approach the region. Light precipitation is expected Tuesday night into Wednesday morning. Totals are pretty shaky at this point but I'm not expecting anything significant.

Avalanche Summary

There have been numerous avalanches both natural and human triggered from Size 2 - 3 in the adjacent forecast areas where avalanches have been failing near the ground on the crust/facet combo recently. If you have any observations from the field, please drop us an email: [email protected].

Snowpack Summary

We're off to a good start for early December with upper elevation snow depths that average a meter. It's been almost two weeks since our last significant storm and since that time the snowpack has suffered an unrelenting barrage of wind from around the compass rose. Wind exposed terrain is now a mixed bag of wind effected snow that varies from old hard windslabs to fresh small windslabs and everything in between. To travel safely at & above treeline you need to be able to recognize and avoid these potentially dangerous windslabs. This is the first part of the avalanche problem.Getting a little lower in the snowpack reveals some ugliness. A raincrust sits above large striated facets (sugar snow) on the ground. This is the classic Rockies house of cards setup that professionals throughout the region are concerned about. With numerous recent avalanches failing in this layer in the Rockies recently the chance of a large full depth avalanche remains a concern for backcountry travelers this weekend. Triggering an avalanche in this weak layer will result in a large & destructive avalanche that will likely be unsurvivable.This problem will not go away anytime soon. If I was putting together plans this weekend I'd be combing through my terrain atlas (google earth) looking for slopes around treeline that are protected from wind. Once you're out in the field stay off of terrain features that are thin and weak. Rock's and/or tree's poking out of the snow are a good indication of thin weak snow. It's good practice to avoid terrain that is steep and rocky in general right now. Remember, it's only December and our snowpack needs some time to mature before we even start thinking about the bigger more committing terrain.

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