Bulletin d’avalanche

Jasper

Mar 13 – 14, 2017Parks Canada
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Archivé · expiré 10 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

Weather models are not agreeing to the timing whether Wednesday's or Thursday  will have rising freezing levels and significant rain in valley bottom. Expect  danger to increase if with possibly 20mm of precipitation.   

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    SW winds creating slabs on lee and pressing snow on windward aspects. May be overtop decomposed SH layer on CR 30cm down on South TL aspects.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    Expect an increase in loose wet surface avalanches particularly when the sun comes out, temperatures remain warm, or rain occurs. Rising freezing levels will increase this danger at all elevations. Use caution around terrain traps.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–4
    Natural activity has subsided but don't let your guard down. It remains a major concern with a extremely weak base of depth hoar. Trigger spots would be shallow zones or a step down effect if upper layers are initiated.

Weather Forecast

Tuesday will be steady 20-40km/hr SW winds, clouds, flurries, and freezing level 2100m. Winds will slightly increase speed on Wednesday plus there may be very warm temperatures, significant snow at high elevations, and rain low down Wednesday afternoon into Thursday. The models are not agreeing so allot of uncertainty on outcomes.

Snowpack Summary

Steady moderate Southwest winds transporting and pressing recent 20-40cm of snow into a slab in open areas at TL and above. Generally its bonding to the old snow interface in most areas. The mid-pack consists of persistent slab layers intermixed with weak facets. The base is weak facets, depth hoar, and an ice crust from November.

Avalanche Summary

Monday's patrol observed several wet loose size 1's running in the storm snow at treeline in the Big Bend area. They were likely triggered by solar radiation.  March 11 skiers reported remotely triggering from 300m away into the alpine two size 2.5's 1.5m thick and 35m wide. They ran to bottom of the path.

Confidence

Freezing levels are uncertain

Régions couvertes