Bulletin d’avalanche

Waterton Lakes

Dec 23 – 26, 2020
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Archivé · expiré 6 years ago

Danger d’avalanche

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

Points saillants

Give the new snow time to settle and be mindful of the reverse loading that occurred during the storm. New snow may stress buried weak layers. Our increasingly complex snowpack warrants a cautious approach over the holidays.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2

    Variable wind direction over the forecast period means wind slab may pop up in unexpected areas. Look for wind effect at the surface and avoid exposure terrain with high consequence.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1–3

    Old wind slab sits on top of the Dec 9th melt freeze crust making it a persistent slab The Dec 9th crust is buried 20-80cm deep at Cameron Lake. This layer has not been reactive yet, but there is a chance that the new snow will stress this weakness.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2

    Storm slabs are the primary problem Wednesday. Storm slabs may be more reactive on northerly aspects where wind has stiffened slabs. We expect this problem to transition to wind slab by the end of the week.

Weather Forecast

Tonight: Trace amounts of snow with moderate North wind. Freezing level valley bottom.

Wednesday: Cloudy with sunny periods. Moderate Westerly wind. Possible alpine temperature inversion at Cameron Lake.

Thursday: Sunny With cloudy Periods. Moderate Westerly wind. Alpine temperature inversion at Cameron Lake.

Snowpack Summary

30cm of new snow arrived with a moderate Northerly wind causing reverse loading. New snow has a rain crust below 1900m within the storm slab. These new storm slabs sit over a thick persistent slab which overlies the Dec 9th melt freeze crust. The mid snowpack is well consolidated with a ice crust forming the base of the snowpack.

Avalanche Summary

Storm conditions obscured Alpine limiting observations.

No avalanches observed at the treeline elevation at Cameron Lake.

Treeline snow depth at Cameron lake up to 1.5m with amounts tapering quickly at lower elevations and in other areas of the Park.

Confidence

Régions couvertes