Bollettino valanghe

Northwest Coastal

Dec 8 – 9, 2015Avalanche Canada
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Archiviato · scaduto 11 years ago

Pericolo valanghe

Thu
Fri
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato

In sintesi

Avalanche danger is expected to decrease as things dry out and cool off.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    3–6
    Natural avalanche activity should taper off as things dry out and cool off. However, storm and wind slabs will likely remain susceptible to human triggers for the forecast period.

Avalanche Summary

Recent reports of natural, rider and remotely triggered large slab avalanches from the mountains around Shames suggest that the load on a layer of recently buried surface hoar has reached critical levels.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

The stormy pattern is expected to continue on Wednesday before a drying trend later in the forecast period. Wednesday: Expect another 10-15cm with freezing levels dropping to 800m and moderate southwesterly ridgetop wind. Thursday: 5-10cm of snow with freezing levels dropping to valley bottoms and moderate southeasterly ridgetop wind. Friday: Mainly cloudy with light flurries possible. Freezing level around 500m and light westerly ridgetop wind.

Snowpack Summary

Sustained snowfall continues to load the old snow surface from late November, which may be getting down close to a metre at treeline elevations. These fresh storm and wind slabs are bonding poorly to a variety of weaknesses including crusts, facets and buried surface hoar. The most critical of these is the buried surface hoar, which has the potential for remote triggering, wide propagations and prolonged sensitivity to triggers. It is likely lurking in most sheltered areas treeline and below and has been spotted well into the alpine in Bear Pass. Deeper in the snowpack, weak crusts and facets near the ground maintain the possibility of step-down deep slab triggering.

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