Avalanche forecast

South Columbia

Jan 24 – 25, 2013Avalanche Canada
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Avalanche danger

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

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–6
    The load from the storm snow could awaken the early January surface hoar layer. Distribution is patchy in sheltered areas and has been more reactive below treeline.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    Expect to find thick storm slabs on lee ridges of W-SW winds in the alpine and at treeline and softslabs and loose snow in sheltered areas. We suspect that these layers will not to bond well with the old surface.

Confidence

Poor - Intensity of incoming weather is uncertain

Weather Forecast

Thursday night and Friday: Another frontal system is moving towards the region. Light precipitation (moderate over the Western part of the region) is expected to start overnight and go until the afternoon Friday for a total of 10 to 20 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

Storm snow was already starting to sluff easily far and fast in steep terrain yesterday afternoon. Soft slabs were also forming and were starting to react to skier traffic. Suspect more of that kind of activity today.

Snowpack Summary

More snow will add on to the 20 to 40 cm that fell yesterday with moderate winds from the W-SW. New windslabs in the alpine and at treeline under lee ridgetops will grow thicker and their bond to the old surfaces will be weak for a certain time. Soft slabs and 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. This significant new load (over 40 mm of water equivalent) might also awake the early January surface hoar weak layer that will be sitting down 80 cm in sheltered areas below treeline. 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.

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