Avalanche forecast

Northwest Coastal

Dec 25 – 26, 2012Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Wind slabs have formed in response to down-valley winds. These could be triggered by the weight of a person or snowmobile.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–7
    A deeply buried weakness may be triggered from thin, rocky snowpack areas or with a large trigger.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Thursday

Weather Forecast

Wednesday: Light SW winds. Strong arctic outflow winds in the valleys. Alpine temp -8. A few cm snow.Thursday: Light SW winds. Alpine temp -7. Moderate snow.Friday: Moderate to strong SW winds. Alpine temp around -6. Moderate snow. 

Avalanche Summary

 Several natural size 1-2 loose dry and thin slab avalanches failed in terrain features wind-loaded by outflow (down-valley) winds over the past few days. Explosives triggered size 2-3 slabs which failed near the ground in facets last weekend.

Snowpack Summary

Wind slabs and cornices have developed on a fairly widespread basis and may be found on many slopes due to variable wind directions. Surface faceting is likely to continue while the weather remains cold. A layer of surface hoar buried in the upper metre of the pack has been observed in the Shames backcountry. The mid-pack is generally well settled. Near the base of the snowpack, a crust/facet layer continues to give hard, sudden results in snowpack tests. This weakness is unlikely to be triggered by a single person, but it remains possible with a very heavy load (e.g. cornice fall) or from a thin-spot trigger point.

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