Avalanche forecast

Jasper

Dec 20 – 21, 2016Parks Canada
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Archived · expired 10 years ago

Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Things have changed significantly in the last 48 hours. Intense South West winds have redistributed cold dry snow and created a touchy windslab condition.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    48 hours of intense ridgetop transport due to strong SW winds has created new windslabs, reactive to skier traffic. Numerous natural avalanches were observed from a variety of aspects, particularly alpine gulley features and planar NE slopes.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    The depth of this crust is now highly variable, and may as deep as 1m in lee areas that have received significant loading due to strong SW winds. Careful evaluation of this interface is essential with this new loading pattern.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Although there has been extensive scouring, the weak facets will likely continue to shed from steep rocky terrain.

Weather Forecast

The calm and very cold weather of the last 2 weeks is over. Milder temperatures expected, with strong SW winds and steady precipitation (25cm possible by Friday in the Columbia Icefield area).

Snowpack Summary

Significant change in the last 48 hours due to intense SW winds and ridge top transport of faceted snow. Expect new wind slabs in lee areas and cross loaded gullies. Suspect surface hoar (Dec 11) in sheltered NE aspects around treeline (2100-2300m). Nov crust is now on the surface in scoured areas and as deep as 1m+ on lee aspects.

Avalanche Summary

Numerous natural wind slabs to sz 1.5 observed today, particularly in alpine gulley features and steep NE aspects. We expect that natural activity was fairly widespread in these types of terrain features, but become quickly obscured and re-loaded. Of note, one size 2 with impressive propagation (~250m) observed on Parker slab, NE, at 2200m.

Confidence

Intensity of incoming weather systems is uncertain

Regions covered