Avalanche forecast

Northwest Inland

Feb 18 – 19, 2017Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Conditions are improving with cooling temperatures, but the lingering possibility of deep persistent slab avalanches warrants extra caution around big slopes.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Watch for reactive wind slabs in exposed high elevation terrain. Wind slabs may "step down" to deeper more destructive layers, including surface hoar buried on February 10th.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    A weakness at the bottom of the snowpack is lingering and may be triggered in shallow snowpack areas or by the weight of smaller avalanches.

Snowpack Summary

5-10 cm of recent snow sits above a rain crust and settling storm snow. Strong winds earlier in the week formed deeper deposits in exposed terrain at higher elevations. About 30-60 cm below the surface, you may find surface hoar that was buried on February 10th. There's a fair bit of uncertainty regarding the reactivity and distribution of this layer throughout the region. A stiff mid pack sits above weak sugary snow near the ground. This basal weakness woke up during the last storm and produced numerous large avalanches that released on the ground. The layer has recently been considered dormant but should still be monitored.

Confidence

Moderate - The weather pattern is stable

Weather Forecast

SUNDAY: Cloudy, light southeast winds, alpine temperatures around -10 C.MONDAY: Cloudy, light southeast winds, alpine temperatures around -8 C.TUESDAY: Cloudy with sunny periods, light winds, alpine temperatures around -8 C.

Avalanche Summary

Recent avalanche observations are limited. On Thursday, a size 2 natural wind slab was reported on a northwest treeline aspect. During the warm storm earlier this week, a few small wet slabs were reactive to ski cutting in the Howsons and very large natural and explosive triggered avalanches were reported in northern parts of the region where deep persistent slabs have been more reactive.On Sunday, watch for reactive wind slabs at higher elevations. Also keep in mind that a basal weakness continues to drive a low probability/high consequence deep persistent avalanche problem for the region. Very large avalanches remain possible, especially in shallow snowpack areas.

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