Boletín de aludes

South Rockies

Mar 7 – 8, 2021Avalanche Canada
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Archivado · caducó 6 years ago

Peligro de aludes

Tue
Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Lo esencial

In areas where the snow surface stayed dry during the heatwave, or there is a breakable crust present, triggering avalanches remains a possibility. In areas where the surface has frozen into a thick crust that supports your weight, avalanches are unlikely.

Problemas de aludes

  • Persistent Slabs

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

    Two persistent weak layers exist in the snowpack. The upper layer is down 30-60 cm and consists primarily of facets. The next layer is down 60-100 cm and consists of surface hoar, facets, and/or a crust. The problem has been most prevalent around treeline elevations and in openings below treeline, but also reaches into the lower alpine. 

    In areas where the snow is dry (soft or wind-affected), or where a breakable crust exists, it may still be possible to trigger a persistent slab.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

SATURDAY NIGHT - Cloudy with clear periods / moderate west wind / alpine low temperature near -8 / freezing level 1500 m and dropping to valley bottom

SUNDAY - Cloudy with sunny periods and isolated flurries / moderate to strong southwest wind / alpine high temperature near -6 / freezing level 

1500 m and dropping to valley bottom overnight

MONDAY - Sunny with cloudy periods / light west wind / alpine high temperature near -7 / freezing level 1500 m and dropping to valley bottom overnight

TUESDAY - A mix of sun and cloud / light southeast wind / alpine high temperature near -6 / freezing level 1500 m and dropping to valley bottom overnight

Avalanche Summary

There were no new avalanches reported on Saturday, at the time of publishing.

On Thursday, there were several reports of natural and human-triggered wet loose avalanches up to size 1.5. There was also a few size 2 solar triggered wind slab avalanches reported on south to southeast aspects. In addition, there were three size 2.5 natural persistent slab avalanches reported in the nearby Waterton National Park region.

There were a few size 1 natural and human-triggered wet loose avalanches reported on solar aspects on Wednesday. There were also reports of several size 2-2.5 natural wet loose avalanches in the neighbouring Waterton National Park region, and two size 2.5 natural persistent slab avalanches in the neighbouring Kananaskis Country region.

Snowpack Summary

Previous warm temperatures followed by a re-freeze have created a crust on the surface in many areas. Dry snow may still be found on north aspects at upper elevations. Wind slabs are likely still present on northerly aspects in the alpine and at treeline. Windward slopes at upper elevations have been scoured down to rocks or crusts in many areas due to recent strong southwest winds. 

40-60 cm (in some places up to 100 cm) of snow sits above a persistent weak layer of facets that was buried in mid-February. There is another persistent weak layer that was buried at the end of January. This layer consists of surface hoar, facets, and/or a hard melt-freeze crust.  

Weak faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack. 

Terrain and Travel

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Minimize your exposure time below cornices.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

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