Avalanche forecast

Banff Yoho Kootenay

Jan 13 – 14, 2018Parks Canada
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Archived · expired 9 years ago

Avalanche danger

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

The snowpack has almost reached tipping point with 40cm of soft snow overlying the Dec. 15 weak layer (surface hoar & facets). Warming temperatures and wind this weekend could push it over the edge at treeline and above.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Soft windslabs formed during the last storm exist near ridge crests and under cliff bands. Watch for the changing feel of the snow under your feet and be wary of areas with denser surface snow.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    There is a dangerous weak layer down 30-40 cm but it needs a stiffer slab overlying it for the avalanche to occur. We are "almost" at that tipping point so be very careful with this layer and travel conservatively even if you observe no avalanches.

Weather Forecast

A warmup is expected starting Saturday with alpine temps in the -3 to 5C range on the Eastern end of the range. Increasing Westerly winds will accompany this and we could see alpine elevation gusts in the 50-80kmh range by the evening with a couple cm of snow. It looks warm through the coming weekend.

Snowpack Summary

30cm snow has fallen over the past week with limited wind effect except near ridge crests. There is now a total of 30-50 cm overlying the Dec.15 persistent weak layer of facets and some surface hoar which is becoming reactive at treeline and above. This layer is producing easy to moderate sudden collapse results. Click for an example from today.

Avalanche Summary

A solo backcountry skier triggered a size 2 avalanche on Richardson's Ridge yesterday outside the Lake Louise Ski Resort boundary - this was a treeline area with a shallow snowpack. As well, numerous small windslabs were observed to have run over the past 48 hours and there has been plenty of settlements being reported at treeline and above.

Confidence

Regions covered