Avalanche forecast

Purcells

Jan 24 – 25, 2013Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    A cautious approach is recommended on steep S slopes and sheltered terrain below treeline.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    New storm slabs were formed with S-SW moderate winds in the alpine and at treeline on lee features. Soft slabs and small loose avalanches could also run easily on the weaker underlying surfaces in sheltered areas.

Confidence

Poor - Intensity of incoming weather is uncertain

Weather Forecast

Thursday night and Friday: Another frontal system is moving inland from the coast. Light precipitation expected to start overnight and go until the afternoon Friday for a total of 5-10 mm. in the wettest zones. Winds are expected to be strong from the SW-W in the alpine and temperatures remaining cool (-7 C) and freezing level staying at the surface. Saturday: Trace to light precipitation amounts, lighter W winds and similar temperatures. Sunday: Similar unsettled conditions providing trace to light precipitation, cool temperatures with light SW winds.

Avalanche Summary

No recent natural avalanche was reported. An explosive shot resulted in a size 2 slab on a W slope which is suspected to have run on the early January weak surface.

Snowpack Summary

More snow will add on to the 10 cm that fell yesterday with moderate winds from the W-SW. New windslabs in the alpine and at treeline under lee ridgetops will form and their bond to the old surfaces might be weak for a certain time. Loose snow is expected to slide very easily on the January 23th surface hoar layer that is located in shaded-sheltered areas below treeline and also on the buried suncrust found on South facing slopes. The early January surface hoar weak layer is still a concern to professionals. It is mostly found under 30-50 cm in the below treeline band and is still producing a variety of test results. Under these concerning layers, a strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive.

Regions covered