Avalanche forecast

Northwest Coastal

Feb 4 – 5, 2012Avalanche Canada
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Avalanche danger

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

Avalanche danger will peak during the heat of the day.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    3–7
    Cornices will be weakest during warm and sunny periods. Cornice fall could trigger an avalanche on the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–6
    Recent rain and warm temperatures promoted avalanche activity at low elevations on a layer of facets buried around 20th Jan. This problem may creep higher in elevation with continued warm alpine temperatures.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Avalanche activity recently spiked in response to warming. Cooler temperatures and cloud cover should decrease this problem on Sunday, but expect storm slabs to become touchy again by Monday.

Confidence

Fair - Freezing levels are uncertain on Sunday

Weather Forecast

The next few days should bring generally benign weather, except on Sunday when a weak disturbance will bring very light snow to the area. Otherwise, expect no precipitation, light winds, cool nights and warm days.

Avalanche Summary

On Friday, slab avalanches up to size 3.5 were reported in response initially to rain and then during the day to intense solar radiation. On Thursday, numerous large (up to size 3) slab avalanches were reported out of lee terrain (SW predominantly) along Bear Pass during the warming period as the snow turned to rain. Lower elevations were especially active.

Snowpack Summary

Total snowpack depths pushing 5m at treeline are at new record levels for this time of year. Recent warm temperatures helped settle storm snow into a touchy surface slab at lower elevations. Other weaknesses can be found within the upper snowpack and the Jan. 20th facets down around 150cm. These create the potential for large step-down avalanches, but things seem to be settling rapidly. Strong winds associated with recent storms means large weak wind slabs and cornices on lee and cross-loaded terrain. Most snowpack concerns are limited to the surface layers. However, large triggers such as cornice falls and smaller avalanches stepping-down could affect deeper weaknesses.

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