Avalanche forecast

Purcells

Feb 6 – 7, 2013Avalanche Canada
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Archived · expired 14 years ago

Avalanche danger

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

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. Areas of concern are in the immediate lees of slopes and behind terrain features like ridgelines and ribs.

  • 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

Good

Weather Forecast

Thursday: A weak upper trough moves through the region bringing unsettled conditions and light snow accumulations of 5 cm. Ridgetop winds will light and blowing from the West. Treeline temperatures near -4 and freezing levels will be around 1100 m. Friday: Ridge of high pressure moves in with residual moisture and cloudy cover bringing only trace snow amounts. Ridgetop winds will switch and blow light from the NW. Treeline temperatures near -6 and freezing levels will be in the valley bottom.Saturday: Ridging continues accompanied by a fast moving, short lived weak disturbance. Trace of snow expected with ridgetop winds blowing moderate from the NW. Treeline temperature near -8 and freezing levels remain in the valley.

Avalanche Summary

Natural loose snow sluffing from steep 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 hoar surface seem to be most touchy. Continued freezing temperatures overnight have helped to strengthen the moist surface layers that developed during warm period last weekend. The mid-pack is generally well settled. The average snowpack depth at treeline elevations is near 130 cm.

Regions covered