Bollettino valanghe

Sea To Sky

Feb 23 – 24, 2018Avalanche Canada
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Archiviato · scaduto 9 years ago

Pericolo valanghe

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

In sintesi

New snowfall likely won't bond well to underlying snow surfaces. Expect old and new slabs on all aspects at higher elevations, loose dry snow in sheltered areas, and looming cornices on ridgelines. Use caution on solar slopes when the sun is out.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–3
    Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect, especially when the sun is out.
  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2.5
    Storm slabs have formed with new snow and strong southerly winds. Expect deeper slabs in lee features and loose snow in sheltered areas. These sit above previous wind slabs. Watch out for natural avalanches on solar slopes when the sun is out.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

FRIDAY NIGHT: Cloudy with snowfall, accumulation 5 to 10 cm, moderate to strong southwesterly winds, alpine temperature -13 C, freezing level below valley bottom.SATURDAY: Sunny with late afternoon clouds, light northwesterly winds, alpine temperature -11 C, freezing level near 600 m.SUNDAY: Cloudy with early-morning snowfall then partly cloudy, accumulation 10 to 15 cm, strong westerly winds decreasing to light over the day, alpine temperature -11 C, freezing level near 600 m.MONDAY: Partly cloudy, light westerly winds, alpine temperature -10 C, freezing level 700 m.

Avalanche Summary

A large (size 3) natural cornice fall was observed, which likely released within the past few days. No slab was triggered beneath it. Otherwise, a small loose dry avalanche was triggered by a skier in steep terrain.Expect natural and human-triggered avalanche activity to increase with the storms and warming sunshine.

Snowpack Summary

Around 10 to 20 cm of storm snow fell with strong southerly winds, producing storm slabs on all aspects with deeper deposits found in lee features. This snow fell on previously wind-affected surfaces. The new snow may not bond well to these surfaces and could be reactive to both natural and human triggers.Deeper in the snowpack, a crust layer can be found on sun-exposed slopes below 1900 m, which allowed for slab avalanches to propagate widely over the past week.Even deeper, avalanche professionals are still monitoring the mid-January crust. This layer is now 150-200 cm deep, but a heavy trigger (such as a cornice fall) or the next major storm (loading and/or warming) could wake this layer up.Also make note of cornices at ridgeline. Variable winds in the past month have produced cornices on all aspects. They will become touchier as they grow in size, as temperatures rise, and as the sun packs a strong punch on clear days. Stand well back of them!

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