Avalanche forecast

Kootenay Boundary

Dec 5 – 6, 2012Avalanche Canada
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Avalanche danger

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

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–5
    A layer of surface hoar buried at the end of November has been responsible for fairly widespread avalanche activity in some areas. Where it exists, this layer may persist for quite some time.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    In some areas relentless snowfall and wind has created an ongoing wind/storm slab problem. Watch for triggering in gullies, below ridge crests and behind terrain features.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–6

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Overnight and Thursday: Light snowfall / strong west winds decreasing to moderate and southwest by Thursday / Freezing level at 800mFriday: Light snowfall / moderate to strong southwest winds / Freezing level at surface  Saturday: Trace amounts of snow / Light north winds / Freezing level at surface

Avalanche Summary

On Wednesday several natural avalanches to size 2 were reported from the region while explosives control produced isolated releases to size 2.5. These releases which occurred at treeline and above are suspected to have run within recent storm/wind layers or on the late November surface hoar.

Snowpack Summary

Recent snowfall amounts have been highly variable, but in deeper snowpack areas up to 85 cm of settled storm snow has fallen in the past week. This snowfall was accompanied by generally moderate to more recently strong and variable winds, forming deep and reactive wind slabs in exposed leeward terrain. Below the recent storm snow is a layer of surface hoar that was buried at the end of November. This layer continues to be reactive. At the base of the snowpack sits the early November rain crust. This layer seems most likely to be found in deeper snowpack areas at higher elevations. I'm not aware of any activity on this layer as of late, but observations have been limited and it may have the potential to 'wake-up' with continued loading.There are significant variations in snowpack structure from one drainage to another. In short, digging down and making your own observations will be critical to safe slope selection. Thank you to those who have shared field observations with us. If you would like to do the same, you may contact us at [email protected].

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