Boletín de aludes

South Rockies

Feb 20 – 21, 2012Avalanche Canada
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Archivado · caducó 15 years ago

Peligro de aludes

Wed
Thu
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–4
    Forecast strong to extreme winds will set up new wind slab behind exposed terrain features in the alpine and at treeline.
  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–4
    While still fairly shallow and therefore likely to produce mostly smaller avalanches, this layer needs to be closely watched, especially as the region receives more snow.
  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    3–6
    Deep and destructive persistent slab avalanches are unlikely, but a large trigger may activate this weakness on a steep, rocky & unsupported area with a shallow snowpack.

Confidence

Poor - Intensity of incoming weather is uncertain on Tuesday

Weather Forecast

Tuesday: A Pacific frontal system arrives bringing 5-10 cm new snow and strong westerly winds, which at ridge top could reach 100 km/h. Freezing levels will spike to around 1600 m in the afternoon. Wednesday: the cold front associated with the system moves through, bringing light amounts of snow and bringing freezing levels down to around 1000 m. Winds should become moderate northwesterly. Thursday: Dry, with light northwesterly winds and freezing levels around 800 m.

Avalanche Summary

Numerous avalanches sized 1.5 were reported on Sunday at all elevations and focussed predominantly on easterly aspects. Remote-triggering was reported, where the avalanche was triggered from up to 100 m from where it initiated.

Snowpack Summary

In southern and western parts of the region, 40-50 cm of recent snow sits of a highly reactive weak layer comprising surface hoar (most prevalent in the west of the region), sugary facets on shady northerly aspects and sun crusts on solar aspects. This interface has started to react to human-triggering. Certain features of the reactivity, such as remote triggering and the ability to initiate avalanches on relatively low angled terrain, point to this weak layer shaping up to be quite dangerous. In areas further north, less snow has fallen on this interface--in the northern Elk Valley for instance, only around 15 cm lies above this interface. In lower snow areas, avalanche activity will likely lag behind higher snow areas. In general, the mid-pack is quite strong in most locations. However, lingering concern remains for basal facets, particularly in shallower snowpack areas with steep, rocky start zones.

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