Boletín de aludes

North Columbia

Dec 31, 2020 – Jan 1, 2021Avalanche Canada
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Archivado · caducó 6 years ago

Peligro de aludes

Sat
Sun
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado

Lo esencial

  

Recently formed storm slabs will be most reactive in wind affected areas at treeline and above. Be especially cautious as you transition into wind affected terrain.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3.5

     Two persistent weak layers buried in early/mid Dec. are now 80 to 150 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can vary significantly from one valley to the next .

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    The 35-50 cm. of recent snow is most likely to be reactive in wind affected areas where the snow has been stiffened into a slab.

Avalanche Summary

There have been numerous recent reports of dry loose avalanches(sluffs) running surprisingly fast and far below treeline.

 

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

  

WEDNESDAY NIGHT: Cloudy with flurries; 3-5 cm. / Light, west ridgetop wind / alpine low temperature -12 / Freezing level valley bottom.

THURSDAY: Cloudy. / Light, west ridgetop wind / alpine high temperature -7 / Freezing level valley bottom.

FRIDAY: Cloudy with flurries; 3-5 cm. / Strong, southwest ridgetop wind / alpine high temperature -6 / Freezing level rising to 1000 m.

SATURDAY: Snow; 10-15 cm. / Strong, southwest ridgetop wind / alpine high temperature -4 / Freezing level 1300 m.

Snowpack Summary

  

30-50 cm. of new snow since Christmas day fell on a mixture of faceted old snow and small surface hoar. The recent snow has been slow to settle into a slab and made for some great riding in many areas. This recent snow is most likely to be reactive in wind affected areas where the snow has been stiffened into a slab.

 Two persistent weak layers buried in early/mid Dec. are now 80 to 150 cm below the surface. The form and distribution of these layers are HIGHLY VARIABLE and have created conditions that can vary significantly from one valley to the next. The first layer down around a metre has been primarily reported as small surface hoar. The next layer has been reported as a thin freezing rain crust, surface hoar, or thick rain crust depending on elevation and location. As a result, diligent investigation of the snowpack is required to get a handle on localized conditions.

Terrain and Travel

  • Be especially cautious as you transition into wind affected terrain.
  • Uncertainty is best managed through conservative terrain choices at this time.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Regiones cubiertas