Avalanche forecast

Sea To Sky

Mar 21 – 22, 2012Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    Wind slabs lurk below ridges, behind terrain features and in gullies. They may be buried by new snow, making them hard to spot.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Variable new and old storm slabs could be triggered on steep or convex terrain.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    4–8
    Persistent weaknesses still have the potential to create very large, destructive avalanches if triggered. Possible triggering mechanisms include a person/sled on a thin snowpack spot, cornice fall, or step-down avalanche.

Weather Forecast

Thursday: Cloudy with flurries - 2-5cm. The freezing level rises to around 800-1000m during the day. Winds are light and variable. Friday: A mix of sun and cloud. Freezing level staying low near 800m. Winds remain light. Saturday: Mainly sunny and milder with the freezing level jumping to 1500m. Winds are light from the southeast.

Avalanche Summary

Avalanche control on Tuesday produced numerous small slab avalanches (10-30cm deep) and a couple slabs up to Size 2, primarily in wind loaded terrain near ridge top. On Monday, a skier triggered a buried wind slab on a convex roll 30-40cm deep on a north-east aspect. Some natural activity was also observed on steep solar aspects.

Confidence

Fair - Due to variable weather conditions

Snowpack Summary

Snow and wind created fresh wind slabs and storm slabs on Tuesday. Heavy snow which fell last week is slowly settling, but variable storm snow weaknesses and buried crusts mean a deep storm slab release is still possible. Cornices are large and threaten slopes below. A persistent weakness, formed in mid-February, continues to produce hard, sudden planar results in snowpack tests. The likelihood of triggering this layer has gone down, but very large avalanches remain possible, which could be triggered by a shallower avalanche or cornice fall. The average snowpack depth at treeline is 350cm.

Regions covered