Avalanche forecast

Kootenay Boundary

Dec 7 – 8, 2012Avalanche Canada
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Avalanche danger

Sun
Mon
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. Human triggering is still likely, especially on unsupported terrain.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Varying amounts of new snow are likely to produce soft slab and loose snow avalanches. If wind values are in the moderate range on Friday night, windslabs may be possible in exposed areas.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–6
    Deep and destructive releases on the early November crust have been observed in a neighboring region. Although not widespread in this region, where it exists this layer may now be primed for triggering.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Overnight and Saturday: Light to locally moderate snowfall on Friday night with clearing on Saturday / moderate southwest winds becoming light and northwest with clearing / Freezing level at 500mSunday: Light snowfall / light northwest winds / Freezing level at surfaceMonday: Light snowfall / light west winds / Freezing level at 700m

Avalanche Summary

No avalanches were reported from the region on Friday. This may speak more to a lack of observations than actual avalanche activity.

Snowpack Summary

Snowfall amounts have been mostly moderate over the past week with significantly greater accumulations occurring in the Kootenay Pass area where well over a metre of snow has fallen since the end of November. Current surfaces most likely include varying amounts of fairly low density storm snow which override windslabs which formed earlier in the week.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 in the Kootenay Boundary region; however, deep and destructive releases have been observed in the South Columbia region (directly to the north). This indicates to me that, where it exists, this layer may now be primed for triggering.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. Any observations from the field are welcome at [email protected].

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