Bollettino valanghe

Northwest Coastal

Dec 13, 2017Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 9 years ago

Pericolo valanghe

Thu
Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

High freezing levels continue but precipitation amounts overnight Tuesday vary through the region. If you receive more than 20 mm consider the avalanche danger to be CONSIDERABLE.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2
    Storm slabs may exist where the recent precipitation fell as snow. Watch for triggering in higher elevation, wind-exposed terrain.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2
    With continued warming and light precipitation, I would expect loose wet avalanches to occur, especially on steep slopes and terrain features well into the alpine.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–3
    Weak layers buried near the base of the snowpack can't be dismissed while new snow or rain load the surface. I'd limit my exposure to large overhead slopes, especially when the sun makes an appearance on Monday.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Wednesday: Mostly cloudy with sunny breaks. Alpine temperatures near plus 5 degrees and freezing levels up to 3000 m. Ridgetop winds moderate from the south.Thursday: Moderate precipitation amounts. Alpine temperatures high of plus 6 degrees with freezing levels 2500 m. Ridgetop winds strong from the southwest. Friday: Cloudy with some flurries. Alpine temperatures near -3 and freezing levels dropping to 800 m. Ridgetop winds light gusting strong from the southwest.Check out the Mountain Weather Forecast for more detail.

Avalanche Summary

On Monday, numerous natural wet slab avalanches up to size 2.5 were reported from upper elevations. Avalanche activity will likely increase through the forecast period with new rain, snow and wind.I'd also remain suspect of the deep persistent layers on your radar as the region receives this new load. On December 7th and 8th a few deep persistent slabs to size 3 out of steep south facing alpine terrain in the Skeena corridor west of Terrace were reported. Basal facets were thought to be the culprit in these events. The deep persistent slab is something to keep on your radar, especially with more weather in the forecast.

Snowpack Summary

Recently, the region has received up to 20 mm of rain and some new snow at high alpine elevations. The alpine and treeline has seen significant wind effect on all aspects including wind slab and wind pressed snow. Snow surfaces are highly variable and consist of rain crusts, moist snow and new dry storm snow at elevations above 1700 m. Below the surface sits a well-settled snowpack overlying several layers of interest. Down 70-100 cm you'll likely find a 5-10 cm thick crust which was buried on November 23 and in some areas, a feathery surface hoar layer down 50-60 cm producing moderate snowpack test results. The widespread crust/facet interface that was buried at the end of October can now be found 100-200 cm deep and exists region wide.

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