Bulletin d’avalanche

Waterton Lakes

Jan 6 – 9, 2015Parks Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

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

A good time to be conservative as a storm threatens to tip the balance on the persistent weak layer. After the storm, watch for a temperature inversion Wednesday that may keep hazard elevated especially if combined with strong winds.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3
    Facets and isolated surface hoar above the Dec 13 crust remain the feature to watch in the snowpack. New load from storms or wind transport will make this more sensitive to triggering especially when combined with warm temperatures Wednesday.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    The snow from the turbulent storm is forming a 30 to 40 cm soft slab at all elevations that fails very easily in tests over the cold low density snow from the weekend. Expect more development of these slabs at higher elevations with more wind effect.

Weather Forecast

15cm, rising temperatures, and gusty alpine winds are expected with the passage of a warm front tonight. Tuesday morning as the cold front passes, expect winds to peak, temperatures to drop, and the precip to trail off. Watch out Wednesday for a strong inversion with freezing levels reaching 3000m and some potential for Strong West winds.

Snowpack Summary

160 to 200cm now at treeline. 30cm of snow accumulated since Friday now forms a very soft storm slab above faceted and wind affected surfaces. Cold temperatures slowed settlement in the 50 to 90 cm slab above the Dec 13 Crust/Facet and Dec 16 Surface Hoar layers. This has also promoted facet development above the crust and weakened this layer.

Avalanche Summary

Monday I triggered a south facing 40 degree slope at treeline by taking off my skis to dig a profile at the top of the start zone. Thankfully, only a 10cm crack formed at the crown in front of my feet, however cracks could be seen up to 50m away down the slope. Subsequent tests produced easy sudden planar shears on facets above the Dec 13 Crust.

Confidence

Freezing levels are uncertain on Wednesday

Régions couvertes