Bulletin d’avalanche

Stevens Pass

Dec 27 – 28, 2015Northwest Avalanche Center
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Archivé · expiré 11 years ago

Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré

Points saillants

New wind slab should be found on a variety of aspects Monday, mainly near and above treeline. Remember MODERATE danger means human triggered avalanches are possible. Recent unconsolidated storm snow is still very deep in places with possible large tree wells lurking, so stick near your partner in the trees. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1
  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1

Detailed Forecast

Wind slab will most likely be found on north to southeast aspects near and above tree line, except locally on west-northwest aspects near the Cascade Passes. NW winds will redistribute new snowfall to lee SE slopes above treeline Monday. Wind and storm slab avalanches should stay within recent storm layers. Test for inverted strong over weak storm snow and give cornices a wide margin.

Beware of loose dry avalanches in steep non-wind affected terrain that could have unintended consequences such as knocking you off your feet and into a terrain trap.

There have been snow immersion fatalities in tree wells already this season at Snoqualmie and in Canada. Recent unconsolidated storm snow is still very deep in places with possible large tree wells lurking, so stick near your partner in the trees and maintain visual contact.  

Snowpack Discussion

For the week ending on Dec. 24th, a snowy and cool storm cycle brought 5-9 feet of snowfall along the west slopes. Only light additional accumulations over the last few days have allowed the snowpack to gradually settle, but it remains deep out there with generally great skiing and riding!  

The upper snowpack should generally be right side up with increasing hardness with depth. Moderate S-SW transport winds with Sunday's system may have built new wind slab on N through E aspects. However, Alpental pro-patrol did observe local east winds at Snoqualmie Pass building thin wind slabs over weaker snow near treeline Sunday.  

The most recent snowpack and avalanche observations include shallow storm slab releases from Alpental pro-patrol during AM control work on Christmas and of a small skier triggered storm slab near treeline in the Crystal backcountry Saturday. Light snowfall on Sunday was not expected to significantly increase the storm hazard.

Régions couvertes