Avalanche forecast

Jasper

Jan 11 – 12, 2015Parks Canada
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Archived · expired 12 years ago

Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Wide variability in the sensitivity of the storm slab over the Dec 20 layer through the forecast area, be cautious out there.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Recent storm snow has settled into a soft slab which overlies a weak layer of facets and surface hoar. Temperature fluctuations and direct solar radiation may lead to an increased likelihood of avalanches.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2
    This weak layer exists below a variable mid-pack at treeline and sub-alpine elevations. Large loads such as a cornice collapse or surface slides could still possibly trigger this deep persistent weakness.

Weather Forecast

Expecting seasonally cold temps and broken skies over the day Sunday. If the sun comes out for extended periods be aware of the possibility of increasing hazard on solar slopes and especially from rocky shallow areas in the sun. So, if you find yourself on a nice steep sunny slope slapping on sunscreen and having lunch, might be best to move on!

Snowpack Summary

Overall, field teams are finding a weak snowpack. The Dec 20 facet/surface hoar layer is out there. It was proving to be very sensitive to fluctuations in temp and solar radiation and showed exceptional propagating properties for having only a weak soft storm slab over it.

Avalanche Summary

A natural avalanche cycle up to sz 3 on south to westerly (solar) aspects occurred over the week. A dramatic temperature inversion at around 2500ms (cold air low/warm above) was actively affecting the slopes.

Confidence

Due to the number of field observations

Regions covered