Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Look for snow surfaces to weaken on sunny slopes as the day progresses. Rollerballs should be easy to spot, so consider moving to shadier slopes once you start seeing these shedding. In more wind-exposed areas, steer around pockets that appear freshly drifted,  especially in more consequential terrain. 

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    We have just enough dry new snow resting over the recent crust that we may see a round of small wet loose avalanches. These slides will generally be confined to sunny aspects, pointing south, but could entrain all the new snow over the crust. Steer around steep solar slopes once you notice the surface getting sticky or if you see rollerballs initiating. Rollerballs and pinwheels are indicators that wet loose avalanches may soon follow. 

    (1/24/2024)

    Rollerballs are sometimes precursors to larger wet loose avalanches. 

    Photo: Josh Hirshberg

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Recent strong west winds have drifted snow into cohesive slabs on leeward features across the zone. These slabs will range in depth depending on location. Look for thicker, denser slabs in areas with more snow, such as closer to the Cascade Crest, up near Holden, and the Stuart Range. Some of these wind slabs will have the potential to propagate widely if they rest over facets or surface hoar above our Early February Crust (EFC). 

    The winds will be light on Tuesday, so look for surface clues like fresh cornices, rippled snow, or pillow-like slabs to help you identify what slopes to avoid.  Shooting cracks and collapses are obvious signs of instability that you should not ignore. 

    (3/23/2023)

    Do your homework as you travel. Tweak small test slopes and look for signs of instability before committing to larger terrain features.

    Photo: Joe Dellaporta

Avalanche Discussion

Tuesday is shaping to be a beautiful day across the eastern mountains as drier air pushes into the region. On Monday, weather stations near Holden picked up the most recent snow (4 inches), with less further south and east. 

On Tuesday, NWAC Forecasters traveled into the Mission Ridge area and found 6-8 inches above the EFC. They also reported reactive wind slabs failing on small surface hoar and facets above the crust. These slabs stayed small (< 1 ft) but easily triggered due to these weak grains. On Friday, an observer traveled up to 8,000ft in the Stuart Range and found little signs of instability. Another observer also found surface hoar over the early February crust, including forecasters on Tuesday at Blewett Pass.

You’ll generally find 3-5 inches of recent snow over the EFC, with more the higher you go. Expect thin conditions at lower elevations with many hazards, such as open creeks, downed trees, and rough surfaces. 

Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at NWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

 

 

 

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