Avalanche forecast

Northwest Coastal

Mar 21 – 22, 2012Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The avalanche danger is expected to rise during the day if we see prolonged sunny periods.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–4
    New wind slabs may be triggered in exposed lee and cross-loaded terrain.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–6
    Cornices are reported to be very large and potentially unstable at this time. A cornice fall could be destructive by itself, and may also act as a trigger on the slope below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Loose wet avalanches are likely on steep sun exposed slopes if the sun is shining.

Confidence

Fair - Due to variable weather conditions

Weather Forecast

Thursday: Scattered flurries with sunny breaks - 2-5cm. The freezing level should rise to 800m during the day. Winds are moderate from the southeast. Friday and Saturday: A ridge of high pressure builds in giving drier and sunnier conditions. The freezing level bounces from valley bottom overnight to around 1000m during the day. Winds are generally light from the south.

Avalanche Summary

Reports from Tuesday include several skier controlled slab avalanches up to Size 1.5 (15-30cm deep), primarily from wind loaded terrain features. There was also one natural Size 2 avalanche observed on a north aspect with a 50cm crown.

Snowpack Summary

20-40cm of new snow sits on the previous snow surface which included a sun crust on southerly aspects, surface facets or surface hoar in cool shady areas, and pockets of wind slab in exposed terrain. A variety of potential weak layers exist between 60 and 120cm deep. These include surface hoar or facets. There has been no recent activity on these layers but they could wake up with heavy triggers like a large cornice chunk or a snowmobile digging its track in. Cornices in the region are reported to be very large and potentially unstable.

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