Avalanche forecast

Sea To Sky

Dec 6 – 7, 2011Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Weak wind slabs may still be lurking below ridge crests, behind terrain features, and in cross-loaded gullies.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–7
    The right trigger (big air onto steep unsupported slope, sled track trenching deep in a thin area) could have disastrous consequences. The greatest concern is in the Whistler area on slopes with variable snowpack depths above 1900m.

Confidence

Good - -1

Weather Forecast

Mostly clear and dry for the forecast period with light northerly winds. The temperature inversion is expected to redevelop with above freezing treeline and alpine temperatures, as well as valley cloud, by Friday.

Avalanche Summary

Avalanche activity has tapered off throughout the week. Although the likelihood of triggering deep persistent slab avalanches is low, the potential consequences are still very high.

Snowpack Summary

Surface hoar is growing, surface snow is faceting, and pockets of weak wind slab may still be lingering on various aspects at and above treeline.Warm temperatures and sun-exposure likely resulted in a surface crust on steep south aspects. Last weekends rain crust is down 20-40cm and extends up to treeline elevations. Basal depth hoar with an associated crust is prevalent in thin snowpack areas, and especially problematic where it is overlying summer firn. Above that, and down 1-2m, are two more crusts mixed with facets, depth hoar, and surface hoar. Time has allowed the overlying snow to gain strength making it less likely to trigger the deeper weaknesses, but if you do hit the sweet spot, such as a shallow area, the resulting avalanche could have very serious consequences.

Regions covered