Bulletin d’avalanche

Kootenay Boundary

Mar 12 – 13, 2018Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Expect avalanche danger to increase as the temperature rises through the day. Danger ratings are rated for the heat of the day when the likelihood of avalanches triggering is highest.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–2
    Fresh storm and wind slabs have formed with recent new snow and moderate southwesterly wind.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3
    Weak layers exist 40-100 cm below the surface, including surface hoar on north-facing terrain and sun crusts on south-facing terrain. These layers may become reactive with the weight of new snow and warming.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2.5
    Surface crusts on sun exposed slopes will break down quickly in the heat of the day. Expect to see the surface snow sluff and gather mass in steep terrain as the day warms up.

Confidence

Moderate - Freezing levels are uncertain on Wednesday

Weather Forecast

TUESDAY: Mix of sun and cloud / Moderate south wind / Alpine temperature 7 / Freezing level 2700m  WEDNESDAY: Mainly cloudy with isolated flurries or rain showers / Light southwest wind / Alpine temperature 5 / Freezing level 2300m  THURSDAY: Mix of sun, cloud and isolated flurries / Light south wind / Alpine temperature -1 / Freezing level 1400m 

Avalanche Summary

Avalanche activity through the end of the weekend into Monday focused on a natural solar induced loose wet avalanche cycle on south and west aspects in the alpine an treeline to size 2. On Friday reports indicate numerous size 2-2.5 natural and explosive controlled storm snow avalanches running on all aspects in the alpine and at tree line. There were also several skier triggered storm slab avalanche size 1.5-2 both Friday and Saturday on north aspects in the alpine and tree line.

Snowpack Summary

Last week's snow has settled and been redistributed by predominantly west and southwest wind on upper shady aspects or has become moist or wet and/or refrozen (depending on the time of day) on slopes facing the sun. On sheltered northerly aspects it may be sitting on a layer of surface hoar.A mix of weak layers exist 50-100 cm below the surface, including small surface hoar on shady aspects and a crust on solar aspects. These layers have consistently been reactive in snowpack tests, suggesting they could potentially remain reactive to human triggers as well. Deeper weak layers that formed in January and December have gained strength and gone dormant at this time. They include several surface hoar and facet layers 1 to 2 m below the surface and a crust/ facet interface near the base of the snowpack.

Régions couvertes