Avalanche forecast

Northwest Coastal

Feb 28 – 29, 2016Avalanche Canada
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Avalanche danger

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

Moderate winds have loaded lee features in exposed terrain and isolated pockets of storm slab may be lingering on steep slopes.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3–6
    Buried weak layers remain a concern depending on where you are in the region.  In thin snowpack areas, large avalanches can still be triggered from thin spots or by heavy loads such as a cornice collapse or smaller avalanche.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Given the recent snowfall and winds I suspect that you can find reactive soft slabs in steep unsupported terrain at most elevations and in wind loaded features in the alpine and at treeline.

Weather Forecast

MONDAY: flurries with accumulations of up to 5cm overnight and 3cm through the day, light to moderate westerly winds, 1000m freezing level. TUESDAY: isolated flurries possible with a clearing trend, moderate westerly winds, 1200m freezing level. WEDNESDAY: mainly sunny, light southerly winds, 1200m freezing level.

Confidence

Moderate

Avalanche Summary

Natural avalanche activity had slowed before Sunday's storm. A couple of recent standout avalanches from the North of the region are worth keeping in mind though. On Wednesday two very large wind slab avalanches are suspected to have run on the early February crust in the Bear Pass highway corridor. On Saturday a ski cut on a shallow unsupported roll produced a smaller avalanche, again on the early February crust. No new avalanches had been reported on Sunday when this bulletin was published. However, I suspect that there was a cycle of natural avalanche activity through the day given the moderate snowfall and wind.

Snowpack Summary

New snow and moderate winds have created fresh storm slabs at all elevations and wind slabs at treeline and in the alpine. Up to 50cm of new snow now sits above old wind effected snow, a crust on sunny aspects, or surface hoar in isolated sheltered and shady locations. An old crust buried around February 12th that extends up to about 2000m can now be found down 60-80cm. Below this, a layer of surface hoar buried late in January remains a lingering concern in the far North of the region. The snowpack at lower bellow treeline elevations may now be too shallow for avalanches in many places.

Regions covered