Bollettino valanghe

Northwest Coastal

Mar 29 – 30, 2013Avalanche Canada
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Archiviato · scaduto 14 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato

In sintesi

Be alert to conditions that change with daytime warming. Danger ratings may exceed posted levels when solar radiation is strong.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–6
    Large developed cornices loom over slopes. Forecast warming will increase the chances of failure with the potential to initiate large avalanches.
  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–6
    In some areas the March 9th layer can be triggered from a distance, propagate across large distances and create surprisingly large avalanches.
  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–4
    Expect loose wet sluffs to fail on sun-exposed slopes.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Saturday

Weather Forecast

No precipitation is expected for the forecast period. Although high cloud is forecast on Saturday, generally clear skies are expected on Sunday and Monday.Winds will be light from the west on Saturday, generally calm on Sunday, then switching to light and southwesterly Monday.Freezing levels will hover at about 1300m on Saturday, 2400m on Sunday and then 1900m on Monday.

Avalanche Summary

In the far north of the region a cornice collapse triggered a size 3 slab avalanche which failed down to glacier ice. In recent days, solar-triggered natural slab avalanches up to 3.5 have been reported in steep terrain, likely failing on the March 9th layer. Loose wet sluffs up to 2.0 have also been reported. As well, a recent size 2.5 slab avalanche was remotely triggered by a skier in the Hidden Lake area near Shames. Once again, the March 9 surface hoar layer was the culprit. Nobody was caught in the slide.

Snowpack Summary

Surface snow has settled with the influence of warm temperatures and surface hoar is growing on shaded slopes. Solar aspects and lower elevation terrain are now well into a daily melt-freeze cycle. Wind slabs may be found at alpine and treeline elevations on many aspects due to variable winds.Between 50-75cm below the surface is layer of surface hoar buried on March 9th which is variably reactive. In some areas it is stubborn and requires a significant trigger, while in other areas the layer is well preserved and primed for human triggering with the potential for very large avalanches. Check out the Forecaster's Blog for related discussion.The mid snowpack is generally well settled and strong. Having said that, basal facets may resurface as a concern with spring warming, particularly in the north of the region.Cornices are large and untrustworthy, especially when the sun is out.

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