Avalanche forecast

Waterton Lakes

Mar 17 – 19, 2015Parks Canada
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Avalanche danger

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

Up high, fresh, thick new storm slabs exist in many start zones: limit your exposure to these until they have some time to settle. Down low, the snowpack is recovering from the heavy rains and will be rapidly effected by any warming. 

Avalanche problems

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1
    Skiers in steep terrain can expect the surface snow to sluff. Manage yourself and your group carefully to avoid getting caught by these small avalanches. Avoid terrain where a sluff could trigger a more significant storm slab.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    New slabs sitting on a newly formed crust can be found at all elevations but are much more significant at the upper limits of treeline and the alpine. These will be more reactive in steep or unsupported terrain and may be ripe in many start zones.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    As temperatures increase this week watch for moist snow to develop at lower elevations where most of the snowpack has yet to refreeze. If the sun comes out this will happen quickly on solar slopes.

Weather Forecast

Freezing levels will rise to 1800m Tuesday with up to 10 cm expected late in the day with light winds. Freezing levels will reach 2000m with West winds Wednesday as the precip tapers off midday. Expect some sun and even higher freezing levels on Thursday with a SW flow bringing warming for the end of the week.

Snowpack Summary

20 to 30 cm of new snow now sits above a rain soaked snowpack to 2000m. At higher elevations the amount of moist snow now buried gets shallower and the new snow amounts grow quickly to 60cm at 2200m. A new rain crust has formed as the moist snow begins to refreeze. NE winds deposited the new snow in a reverse loading pattern along ridge crests.

Avalanche Summary

Visibility has been poor for the last few days but some size 2.5 debris piles can be seen below the clouds in the run-outs in several of our large alpine paths. We suspect the storm snow is failing as a soft slab and running on the new rain crust or entraining the moist snow below. The surface snow sluffs easily with skier traffic in steep terrain.

Confidence

Timing or intensity of solar radiation is uncertain on Thursday

Regions covered