Avalanche forecast

Banff Yoho Kootenay

Feb 5 – 6, 2018Parks Canada
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Avalanche danger

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

The danger has been reduced to considerable, however human interaction with avalanches is still very likely on steep terrain and terrain uniform features.Our Wx stations are currently down, we are working on getting them back online ASAP.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3.5
    Three weak layers exist in the upper snowpack: Jan 16, Jan 6, and Dec 15. All are a mix of sun crust, surface hoar and facets depending on the aspect and elevation. Destructive avalanches have occurred on these and will continue over the few days.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    20-40cm of storm snow (and wind) has developed a reactive slab at higher elevations. If triggered this layer has the potential to step down to deeper instabilities. Continue to make conservative route choices.

Weather Forecast

A slight cooling and clearing trend is expected for Monday. The wind is also expected to die down and shift to the west. However, the moment of respite will be short lived. Another storm is expected to arrive midday on Wednesday bringing warm temps, precip and an increase in wind. We expect the danger to rise significantly at that time.

Snowpack Summary

Up to 40cm of storm snow (48hrs) and strong wind have created slabs that are primed for human triggering. The main concern in the snowpack continues to be the 3 persistent weak layers of surface hoar and/or facets that are found between 50 and 100cm down. We continue to observe sudden test results, whumphing and large propagations on these layers.

Avalanche Summary

Natural activity was directly observed across Bow Lake today. A cornice released off of a cliff and triggered the slope below it, size 2. An avalanche control operation produced 3 size 3 avalanches on West facing avalanche paths on 93N. The debris ran to mid run out. Additionally, evidence of a widespread cycle up to size 3 was observed.

Confidence

Due to the quality of field observations on Monday

Regions covered