Boletín de aludes

Jasper

Mar 21 – 22, 2017Parks Canada
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Archivado · caducó 10 years ago

Peligro de aludes

Thu
Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado

Lo esencial

Wind transportation and solar radiation will both rapidly increase the avalanche danger

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–3
    60cm of storm snow over the past week has formed a dangerous windslab. Wide crowns up to 2m and a km long have been seen across the range. In shallow areas several of these stepped to ground. All are running a long way into the valley.
  • Cornices

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–3
    Large cornices on lee features some visibility detaching. Those that have released are triggering large avalanches from alpine terrain
  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–4
    The widespread observations of large and deep avalanches indicates strongly that many of the weekends avalanches went on this layer particularly where the snowpack is shallow and in rocky start zones.

Weather Forecast

Freezing level remaining at 1900 overnight with light SW winds. Gradual cooling tomorrow afternoon  with highs of -5 in the alpine and winds increasing to strong. Snow flurries to 5cm for upper elevations. Nearer to the townsite some sunny skies and warmer temperatures

Snowpack Summary

Wind slabs up to 1.5m's thick at and above treeline. Large cornices loom above. Below the slab is a mid-pack with several crusts and persistent instabilities of facets and surface hoar. Closer to the ground a weak base around the November rain crust and depth hoar below. More time is needed for the snowpack to strengthen after the recent loading.

Avalanche Summary

A widespread avalanche cycle took place over the weekend with crowns up to a kilometer long and in places 2m deep. The largest are size 3.5 and have run full path several stepped to basal layers near ground. From treeline less activity and more in the class 2-2.5 range. Control work on Monday produced numerous size 3 avalanches from the alpine.

Confidence

Freezing levels are uncertain on Thursday

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