Bollettino valanghe

South Rockies

Feb 28, 2017Avalanche Canada
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Archiviato · scaduto 10 years ago

Pericolo valanghe

Tue
Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Apri la mappa completa

In sintesi

Fresh and reactive wind slabs will continue to form as the winds increase over the next couple of days.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2
    Recent storm snow may remain loose and unconsolidated in some areas, but human triggerable slabs are possible in areas where the storm snow has been transported by the wind, or settled into a slab.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–4
    A weak layer near the base of the snowpack has the potential for large avalanches, especially in areas with minimal rider compaction or thin variable snow cover.

Confidence

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

Weather Forecast

A change in the weather pattern is upon us as the jet shifts to a westerly flow allowing a series of Pacific frontal systems to track across the Interior regions.Tuesday: Mix of sun and cloud. Alpine temperatures near -14 and ridgetop winds moderate with strong gusts from the West. Wednesday: Cloudy with scattered flurries 5-10 cm. Alpine temperatures near -12 and ridgetop winds moderate with strong gusts from the West. Thursday: Mostly cloudy with a trace of new snow. Alpine temperatures near -10 and ridgetop winds moderate-strong from the West. Freezing levels rising to 1200m.

Avalanche Summary

On Sunday, numerous natural storm slabs were reported up to size 1.5 from steep NE terrain at 2200m. The deep persistent slab problem is a low probability/high consequence scenario that warrants extra caution around large open slopes, especially in shallow snowpack areas. There was a report last Tuesday of a size 3.5 avalanche at Mt Hosmer in the Lizard/Flathead region that released on or stepped down to the deep weak layer near the ground. On Wednesday we had a report from the Lizard range of another size 3.0 deep persistent avalanche on a northeast aspect in the alpine.

Snowpack Summary

Up to 20 cm of storm snow fell on Saturday night, with Castle Mountain being the clear winner. This storm snow sits on last weeks ageing storm slab. The mid-pack in this region is well settled, but the bottom third of the snowpack is composed of weak facets (sugary crystals). Recent snow profile tests have produced moderate failures that released suddenly down 75 cm on the facetted crystals. In the Crowsnest North late last week up to 35 cm of recent storm snow lies above various old surfaces. Near Elkford up to 20 cm of old storm snow sits above a melt/freeze crust. Approximately 100-120 cm of settled snow sits above the weak layer of sugary facets that developed during the cold spell in December. Snow profile tests indicate hard shears in this location where the facets are sitting on a hard wind crust.

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