Bulletin d’avalanche

Northwest Coastal

Mar 25 – 26, 2018Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Tue
Wed
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué

Points saillants

Avalanche danger will increase over the day as the next storm pulse brings heavy snow, strong winds, and rising freezing levels.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–3
    Heavy snowfall is expected to pair with strong winds to create touchy new storm slabs over Sunday night and Monday. Very large avalanches may result if storm slabs release over the melt-freeze crust or surface hoar that is already 30-60 cm deep.

Confidence

Moderate -

Weather Forecast

Sunday night: Flurries bringing approximately 10 cm of new snow. Moderate to strong southwest winds.Monday: Continuing periods of snow bringing approximately 20 cm of new snow. Strong southwest winds, gusting to extreme at high elevations. Freezing level to 900 metres with alpine high temperatures around -2.Tuesday: Mainly cloudy with continuing scattered flurries 3-5 cm of new snow. Strong southwest winds. Freezing level to 800 metres with alpine high temperatures around -3.Wednesday: Mainly cloudy with isolated flurries and a trace of new snow. Moderate to strong west winds. Freezing level to 800 with alpine high temperatures around -3.

Avalanche Summary

Reports from Saturday showed ski cutting in the Bear Pass area producing both slab and loose dry avalanches to size 1.5. Slabs failed all the way down to the melt-freeze crust buried 60 cm deep at treeline on north aspects. No new avalanches were reported in the south of the region. Poor visibility led to limited observations throughout the region.On Saturday, the strong westerly winds were responsible for triggering a couple of wind slabs up to size 1.5 from north-easterly aspects in the alpine. On Friday and MIN reported a rider triggered wind slab avalanche size 1.5 from a southwest aspect. The person rode out of the avalanche and the crown was reportedly 35 cm deep. Friday also saw a natural cycle up to size 2.5 in the recent storm snow.

Snowpack Summary

The past week of stormy weather brought 30-60 cm of new snow to the region. Strong easterly winds initially redistributed the new snow onto leeward aspects, forming thick wind slabs. More recent and forecast strong southwest winds are likely to continue building wind slabs on north through east aspects. Beneath the wind effect, the new snow overlies a plethora of old snow surfaces, including a layer of surface hoar existing on high shaded aspects as well as a melt-freeze crust on all aspects at treeline and below.Deeper in the mid-pack, layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm exist from mid- and late-February and a surface hoar/ crust layer from January is buried around 150 to 200 cm. Near the bottom of the snowpack, sugary facets exist in colder and dryer parts of the region, such as the far north. These buried layers are currently dormant.

Régions couvertes