Avalanche forecast

South Columbia

Jan 26 – 27, 2015Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

The BC interior is experiencing record warm temperatures. Conservative decision making is recommended until conditions cool off.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–5
    A layer of weak surface hoar siting on a crust is buried by 20 to 50 cm of moist snow. This layer will remain a concern as it adjusts to the warm temperatures.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Warm temperatures will increase the likelihood of loose wet avalanches on steep slopes at lower elevations and alpine features exposed to the sun.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    A deeper layer of surface hoar is still producing the occasional large avalanche. It is especially a concern on open slopes around treeline. Small avalanches or cornice collapse could step down to this layer increasing the consequences.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

A cold front will start to push the record breaking warm temperatures out of the interior by Tuesday afternoon. Freezing levels are expected to return to valley bottom Wednesday evening. The region may see isolated flurries and/or showers in the wake of the front. Winds will be light to moderate from the southwest.

Avalanche Summary

We are still in a complex avalanche scenario where touchy conditions are likely to persist. A snowpack with several critical avalanche layers has been stressed first by new load and now by record breaking warm temperatures.  This is resulting in a prolonged and widespread avalanche cycle that has produced avalanches up to size 3.5.  Until freezing levels drop I anticipate that natural avalanches will remain possible and human triggered avalanche likely.  The mid-January surface hoar layer has been responsible for the majority of the recent avalanche activity.  I suspect that a large enough trigger in the right spot could have the potential to wake up the deeper mid-December surface hoar especially in open terrain at treeline. Loose wet and wet slab avalanche are possible while the freezing levels remain high.

Snowpack Summary

The upper snow pack is settling rapidly and moist to wet snow can be found on all aspects and elevations. A crust may be encountered at or just below the surface.  The mid-January surface hoar layer can be found between 40 and 70 cm down.  It is currently my greatest concern.  The midpack is broken by the mid-December surface hoar layer that is now 80 to 140cm below the surface.  Snowpack tests indicate this layer is gaining strength in many areas although it remains a concern especially in open terrain at treeline.

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