Avalanche forecast

Jasper

Dec 19 – 20, 2018Parks Canada
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Archived · expired 8 years ago

Avalanche danger

Fri
Sat
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

More forecast snow and strong winds will increase the avalanche danger into the weekend.Avalanche control is planned between Parkers Ridge and Sask. Crossing on Wednesday Dec. 19th. Expect intermittent closures.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    Moderate SW winds have built windslabs particularly at ridge-tops. These are sensitive in the loading zones, most notably NE exposed treeline and alpine features.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–3.5
    Determining the strength of bond at the Dec11th interface is key to safe travel in avalanche terrain.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3.5
    Several recent large avalanches have been the result of the entire snowpack failing on or near the ground due to the weak snowpack structure surrounding this interface.

Weather Forecast

Stormy weather is expected into the weekend as a series of coastal lows bring moisture over the region. The weather models don't agree but 35cm of snowfall could fall between Wednesday and Friday evening with gusting strong westerly winds. A detailed mountain weather forecast is available from Avalanche Canada.

Snowpack Summary

Up to 30 cm of new snow has been blown into fresh wind slabs by moderate SW winds. The December 11th persistent weak layer (facets, crusts and isolated surface hoar) has been buried by up to 80cm of fallen snow - this has been loaded into lee terrain by moderate to strong SW wind. The deep persistent weakness still lingers near the ground.

Avalanche Summary

A lack of visibility is hiding any new avalanches but on Tuesday a field team at Parkers Ridge observed many signs of instability (shooting cracks and whumphs) and spooky sudden result in snow pits. Last week, a natural avalanche cycle and subsequent avalanche control work resulted in many slab avalanches up to size 3.5 in the Parkers ridge area.

Confidence

Timing, track, or intensity of incoming weather system is uncertain.

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