Bollettino valanghe

Banff Yoho Kootenay

Dec 21 – 22, 2015Parks Canada
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Archiviato · scaduto 11 years ago

Pericolo valanghe

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

In sintesi

Windslabs continue to develop in the alpine. Concern remains for the Dec 3rd persistent weak layer, dig frequently to check for presence of this spotty surface hoar problem and keep a watchful eye on the character of the slab above it. TH

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2
    New isolated slabs soft slabs are steadily growing in alpine terrain. These fresh slabs are easily triggered by skiers and will be found in the immediate lee sides of prominent features. Fragile recent cornice growth has also been failing naturally.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    1–2
    The slab above this layer has facetted out in many areas which has lead to a decrease in triggering however tests continue to produce significant shears. Be cautious in aggressive terrain or in wind affected areas where the slab may retain strength.

Weather Forecast

Westerly flow will bring light amounts of precip under mainly cloudy skies with light to moderate alpine winds over the forecast period. Expect 10cm total through Wednesday. Temps will drop a bit from highs near -10 to as low as -25 at treeline overnight Monday corresponding with some clearing and diminished winds that evening.

Snowpack Summary

10 cm of recent snow has added to the faceted slab over the Dec 3 Surface Hoar now 30 to 50cm deep. While significant shears persist on this layer in isolated, shaded and sheltered areas from 1700 to 2150m, the slab above it continues to lose strength. Meanwhile moderate SW winds are steadily building slabs behind prominent features in the alpine.

Avalanche Summary

Reports citing windslabs up to size 2 in the alpine sensitive to skier traffic have come in over the last 24 hrs as well as a few natural cornice events. Small loose dry activity has also been seen at treeline and above, while these are of minimal consequence at this time in all but extreme terrain, their size is likely to increase.

Confidence

Due to the number of field observations

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