Bollettino valanghe

Northwest Inland

Dec 29 – 30, 2013Avalanche Canada
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Archiviato · scaduto 13 years ago

Pericolo valanghe

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

In sintesi

We're expecting moderate snow and very strong upper winds over the next 24 hours. Areas that don't see much snow could see slightly lower avalanche danger on Monday.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–5
    Despite the recent snowfall many areas are still below average for snow depths. Deep persistent weaknesses may still exist near the base of the snowpack and could be triggered from thin spots or by continued loading from snow and wind.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–4
    Another system is set to spread light to moderate snow amounts with strong W-SW winds through Monday. Expect wind slabs to continue building in exposed lee and cross-loaded terrain. 

Confidence

Poor - Due to the number of field observations

Weather Forecast

Tonight and Monday: Moderate snowfall 5-10 cm. The freezing level is generally around 500 m but an above freezing layer between 1000 and 1500 m is possible. Winds are moderate to strong from the SW. Tuesday: A mix of sun and cloud with a chance of flurries. The freezing level is near valley bottom and winds are light to moderate from the northwest. Wednesday: Another frontal system approaches the coast and could bring periods of snow later in the day. The freezing level is around 500-800 m.

Avalanche Summary

There are a couple reports of recent natural avalanche activity from the Ashman and Hankin areas. In Hankin a couple large slab avalanches (~size 2.5) were observed on northeast facing terrain near ridgetop. These likely released during previous storm and/or wind events and appeared to release near the base of the snowpack. In Ashman a couple smaller storm slabs were observed on steep convex rolls from south facing slopes.

Snowpack Summary

The past few days have brought around 60-70 cm of storm snow with steady strong W-SW winds and fluctuating freezing levels. The most recent storm snow came in with rising temperatures and is likely "upside down" feeling, meaning more dense on top. Expect touchy wind slabs in exposed lee terrain and cross-loaded features well into treeline. A number of rain crusts may exist in the upper and mid snowpack, primarily below 1500 m. Deeper in the snow pack a layer of facets/surface hoar formed in early December may be found in the top 100cm in the Ashman area. The mid and lower snowpack is still structurally weak and faceted. Depth hoar and an early season crust exist near the ground.

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