Avalanche forecast

Jasper

Dec 17 – 18, 2018Parks Canada
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Avalanche danger

Tue
Wed
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

We have a very complicated snowpack that requires a thorough assessment before committing to any avalanche terrain. Large whumphs and shooting cracks were noted on Saturday. Ice climbs with overhead hazard should be avoided until the hazard abates.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–3
    Moderate SW winds continue building windslabs particularly at ridge-tops. These were sensitive in lee areas, most notably NE, treeline and alpine features.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    Determining the strength of bond at the Dec11 interface is key to safe travel in open features at treeline and below.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3.5
    The weak Oct25 crust-facet interface is found 20-30cm off the ground. There is serious potential for step-down avalanches if you trigger the wind or storm slab.

Avalanche Summary

A natural avalanche cycle and subsequent avalanche control work resulted in many slab avalanches up to size 3.5 in the Parkers ridge area on Dec 14th. Saturday's field team toured on Parkers Ridge summer trail (ATES 2) and observed many common signs of instability, like shooting cracks and whumphing.

Confidence

Intensity of incoming weather systems is uncertain on Monday

Snowpack Summary

New snow on the horizon, following recent storm snow, 60cm since Dec 11th in the Icefields region. New snow has been and will continue to be redistributed by moderate SW winds. This interface, Dec11, overly several weak interfaces such as facets, crusts and isolated surface hoar. The deep persistent weakness still lingers near the ground.

Weather Forecast

Monday will be flurries, 8cm of snow, alpine temperature High -5 C and ridge wind southwest 20 km/h gusting to 50 km/h. Tuesday to Wednesday is much the same with potentially 36mm of precipitation from Monday to Wednesday. A detailed mountain weather forecast is available from Avalanche Canada.

Regions covered