Avalanche forecast

Banff Yoho Kootenay

Feb 11 – 12, 2015Parks Canada
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Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Touchy avalanche conditions right now. Explosives continue to trigger large avalanches with 95% of the shots. It is a good time for conservative terrain choices!

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    2–3
    Fifty 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.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3
    A weak temperature crust overlies isothermal conditions at treeline and below elevations. Many loose wet avalanches that have gouged down to ground have been observed in past 48 hours.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–4
    The base of the snowpack remains weak due to basal depth hoar/facets. Additional snow load, or a storm slab failure may trigger large to very large avalanches in thin snowpack areas.

Weather Forecast

The warm weather continues. Freezing levels will be rising to ~1900m during the days with light freezes overnight. Little precipitation in the forecast period with partially cloudy skies. Winds have been light but will be picking up to moderate from the West starting on Wednesday.

Snowpack Summary

45 - 70 cm of recent storm overlies a crust from January 30th. The recent heavy precipitation, and warmer temperatures have created very touchy storm slabs over top of the January 30th crust interface. Despite a weak freeze last night isothermal conditions persist at treeline and below.

Avalanche Summary

Avalanche control over the past four days in Banff, Yoho Park and Kootenay Park have produced numerous avalanches up to size 3. 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

Due to the number and quality of field observations

Regions covered