Avalanche forecast

Kootenay Boundary

Apr 1 – 2, 2016Avalanche Canada
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Avalanche danger

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

A Special Warning is in effect. Choose your route to avoid exposure to sun-baked terrain and slopes overhung by cornices.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–5
    Large fragile cornices threaten many slopes. A cornice fall could trigger a large avalanche on the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Persistent slabs may wake up with the prolonged warming, or be triggered by cornice fall.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Loose wet avalanches are likely on all steep slopes, especially those getting baked by the sun. Wet slabs are possible too.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Hot weather continues through the weekend, with the freezing level around 2500 m.  A brief disturbance on Saturday may bring some cloud and light drizzle before mainly sunny days on Sunday and Monday. A front passing through late on Monday is expected to bring light precipitation, with the freezing level around 2000 m.

Avalanche Summary

A natural cycle of size 1-2 loose wet and wet slab avalanches was reported on Wednesday and Thursday. Similar activity is expected to continue until temperatures cool.

Snowpack Summary

Large cornices overhang alpine slopes and threaten to trigger avalanches on slopes below. These are likely to be fragile due to the warm weather. The snow surface is moist up to at least 2000 m on all aspects and may still be dry on shady aspects at higher elevations. At low elevations, the snowpack is isothermal. The late February surface hoar/ crust interface (down 80 to 130 cm) remains a low probability/ high consequence concern. Test results are variable, with occasional sudden planar (pop) results. While generally becoming unlikely to trigger, this layer could produce surprisingly large and destructive avalanches with a cornice fall or warm temperatures.

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