Avalanche forecast

Purcells

Feb 8 – 9, 2013Avalanche Canada
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Archived · expired 14 years ago

Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Blue skies and fresh snow may tempt you into steeper and bigger terrain. Maintain a diligent approach to terrain selection to best manage the current conditions.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    New wind slabs continue to be reactive to light additional loads like skiers and sledders. Areas of concern are in the immediate lees of slopes and behind terrain features like ridgelines and ribs. Cornices have grown and may threaten slopes below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    The recent storm snow continues to settle into a cohesive slab above weak layers and variable old surfaces that comprise of buried wind slabs, surface hoar, and crusts. These weak layers exist 30-50 cm below the surface.

Confidence

Fair - Timing or intensity of solar radiation is uncertain for the entire period

Weather Forecast

A strong ridge of high pressure builds off the coast allowing a cool, dry NorthWest flow over the region with high diurnal variations. Scattered too few clouds will exist allowing some sunny alpine skies on Saturday with more predominant sunny skies on Sunday. Ridgetop winds will blow light-moderate from the NorthWest. Treeline temperatures will hover near -4 and freezing levels rising to 1100 m in the afternoon.

Avalanche Summary

Several small slab avalanches occurred size 1 from steep, cross-loaded terrain features. A skier triggered size 1.5 slab avalanche occurred from a NE aspect at 2300 m. Natural loose dry sluffing continued from steep unsupported terrain.

Snowpack Summary

Wind slabs exist in the alpine and at treeline on lee slopes and behind ridgelines. The recent storm slab continues to settle over old interfaces comprising of surface hoar, crusts and facets down 30-50 cm. However, areas that have buried surface hoar seem to be most touchy. Continued freezing temperatures overnight have helped to strengthen the moist surface layers that developed during warm period last weekend. Watch the duration and intensity of the sun in your local riding area; it may weaken the upper snowpack. Cornices have grown and may threaten slopes below. The mid-pack is generally well settled and the average snowpack depth at treeline elevations is near 130 cm.

Regions covered