Avalanche forecast

Banff Yoho Kootenay

Feb 12 – 13, 2015Parks Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

The natural cycle has slowed down, but the potential for triggering large avalanches is a very real possibility. Watch for how much freeze you get below treeline Thursday, the snow is isothermal below. SH

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3
    Recent winds have created wind slabs in the lee of alpine features.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3
    50 to 90 cm of storm snow exist on the January 30th crust interface. A poor bond exists at this interface and large avalanches have been observed running on this layer. Huge propagations are still possible.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3
    The base of the snowpack remains weak due to basal depth hoar/facets. Initiation of a wind slab or a storm slab may step down to trigger large to very large avalanches in thin snowpack areas.

Weather Forecast

Trace amounts of snow on Thursday, cloudy conditions and freezing levels up to 1700m.  There should be a mild overnight freeze below treeline. 

Snowpack Summary

45-70 cm of recent storm overlies a crust from January 30th. The recent precipitation and warmer temperatures have created touchy storm slabs and wind slabs over top of the Jan. 30th interface. The basal facet/depth hoar layers are still active in shallow snowpack areas. A weak freeze below treeline is barely holding isothermal conditions at bay.

Avalanche Summary

Avalanche control over the past four days in Banff, Yoho Park and Kootenay Park have produced numerous avalanches up to size 3 over the last 4 days. Most of the avalanches started dry and turned wet at lower elevations. Also, evidence of a widespread cycle up to size 3.5 throughout the forecast region. Some avalanches running close to full path.

Confidence

Regions covered