Avalanche forecast

Banff Yoho Kootenay

Jan 21 – 22, 2019Parks Canada
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Avalanche danger

Tue
Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

While natural activity has dropped off, human triggering of a large slab avalanche on the deep persistent layer is a strong possibility. Remain conservative with terrain selection especially in thin snowpack areas.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5
    Southwest winds in the moderate to strong range Saturday created thin, soft slabs in the alpine 10 to 20cm deep.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3.5
    Weak facets and depth hoar are found just above the ground have an significant 50-140cm thick slab sitting above them. While natural  activity has dropped off,  human triggering is still possible. Be very cautious with thin snowpack areas . 

Weather Forecast

Temperatures will continue to cool through to Tuesday morning to -10C to -15C values at treeline.  A weak system will bring modest amounts of snow beginning Monday night with winds increasing to strong in the alpine Tuesday as temperatures climb back to -5 to -10 values at treeline. Cloud and light snow is forecast to continue through Thursday.

Snowpack Summary

5 to 15 cm of recent snow buried suncrusts and some surface hoar. Moderate to Strong SW winds created small soft winslabs in the alpine Friday and Saturday. Of greatest concern are the weak facets and depth hoar in the lower half of the snowpack. In thin snowpack areas (150cm or less) triggering a slab over this layer is more likely.

Avalanche Summary

Very little natural activity has been observed over that last week. A party in the Emerald Lake area triggered a slab during Saturday's storm in lee alpine terrain. Avalanche Control workers at the ski hills have been working with small soft windslabs for the last two days. We have entered a low likelihood, high consequence period for avalanches.

Confidence

Regions covered