Bollettino valanghe

Lizard-Flathead

Feb 12 – 13, 2017Avalanche Canada
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Archiviato · scaduto 10 years ago

Pericolo valanghe

Mon
Tue
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

A Special Public Avalanche Warning Applies to this region. Rapid warming is set to undermine stability throughout the region over the coming days.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2
    Strong winds have been redistributing new snow at the surface into thin wind slabs in lee areas. Solar radiation and warming temperatures will make these fresh wind slabs especially touchy.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3
    Most of our upper snowpack is essentially a storm slab. Its bond to the underlying snow is improving, but steadily rising freezing levels will promote instability on each day of the current forecast period.

Confidence

Moderate -

Weather Forecast

Monday: A mix of sun and cloud. Winds light from the west. Freezing level to 3000 metres with alpine temperatures around +4.Tuesday: A mix of sun and cloud. Winds light to moderate from the southwest. Freezing level to 3400 metres with alpine temperatures of +5Wednesday: A mix of sun and cloud. Strong southwest winds. Freezing level around 3400 metres with alpine temperatures of +5

Avalanche Summary

Explosives control work in the Fernie area on Saturday yielded a few results up to to Size 1 within the wind-affected surface snow. Friday's control work produced numerous storm slab results generally from Size 2-2.5 with two Size 3 results generating from storm loaded north to northeast aspects. Earlier reports from Thursday indicated widespread natural, skier controlled, as well as remotely triggered avalanche activity to size 1.5. One Size 3 avalanche ran naturally in steep alpine terrain in the late afternoon on Thursday.

Snowpack Summary

Strong ridgetop winds have led to roughly 10 cm of wind scoured and pressed new snow at the surface, leaving very little in the way of ski penetration at treeline and above. Below around 1700 metres, the supportive, wind-affected snow gives way to a breakable rain crust. Beneath these variable surfaces lies an estimated metre of storm snow from storms over the past two weekends. The upper half of this layer was deposited as heavy, moist snow, while the lower half is considerably drier and less dense. This 'upside down' storm snow layer lies above a range of previous surfaces that includes wind affected surfaces, a layer of surface hoar in sheltered areas, facets, and/or a thin sun crust. The bond between this earlier storm snow and the old surface is suspected to be improving slowly while hard conditions at the current surface may be diminishing the effect of human triggering. The mid and lower snowpack are generally well settled and stable but isolated basal weaknesses may exist in shallow snowpack areas.

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