Avalanche forecast

Banff Yoho Kootenay

Dec 21 – 22, 2018Parks Canada
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Avalanche danger

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

New snow, wind and mild temperatures will keep the avalanche danger high on Friday. Natural avalanche activity should decrease over the weekend, but human triggering will remain likely! Avoid traveling in avalanche terrain until things improve.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5
    The recent storm snow has almost doubled our snowpack and is failing easily on the Dec 10 interface. Natural avalanches may reach treeline areas. Safe terrain can be found in low angled forest with no exposure to avalanches from above.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1.5–3
    Recent snow has now overloaded the weak middle and lower portions of the snowpack. Avalanches are frequently stepping down to these deeper layers of facets and depth hoar. Avoid traveling in  avalanche terrain.

Weather Forecast

Snow amounts between 10-20cm are expected Thursday night and into Friday morning with mild temperatures and moderate SW winds. A clearing and cooling trend starts on Friday with a ridge of high pressure building for Saturday and Sunday.

Snowpack Summary

A 40-100cm slab of storm snow now sits over the Dec 10th surface hoar/facet interface at treeline and above, with the snowpack almost doubling in the last week. In many areas the lower snowpack is weak and faceted with the October 26th depth hoar and crusts near the base. Snow pack depths range from 90-160cm at ~2000m.

Avalanche Summary

Numerous natural avalanches up to size 2.5, as well as several skier remote and skier triggered avalanches up to size 2 have been observed in the last several days. This pattern is likely to continue for the next while.

Confidence

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

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