Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
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Danger d’avalanche

Thu
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

Wind slabs will be most reactive in the morning hours on atypical aspects. Move cautiously into exposed terrain, steering around steep slopes below sharp cornices or where you find more extensive lens-shaped pillows.  Slabs could overly a slowly healing interface or sit on a crust, so consider evaluating the upper few feet of the snowpack on several aspects.

Problèmes avalancheux

  • Wind Slabs

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

    E winds transported snow down to Pass level on Tuesday and transported moderate amounts of snow near ridgelines. Wind transport could occur through the night near and above treeline and up to around an inch of snow may fall. The north half of the compass is holding onto dry, low-density snow with a weak interface buried about 6" below the snow surface. Much of the surface snow has been redistributed by the winds into reactive slabs reverse-loaded onto W aspects. Avalanches will be more reactive in these locations, particularly in the morning hours. Slabs may become more stubborn by the afternoon given lighter winds and mild temperatures on Wednesday. 

    The southerly half of the compass will have a crust on Wednesday. Wind-blown snow redistributing to those aspects will probably be easily identifiable. If you notice any more expansive deposits of snow above the crust, steer around them on steep slopes.

    With an E wind event, the slopes that typically hold slabs may be scoured and vice versa. Fresh sharp cornices may form on the opposite side of ridgelines from the larger ones that developed over the course of the season. Anticipating fresh slabs below these sharper cornices can be a great way to identify the problem. Also look for warning signs such as wind-stiffened snow, shooting cracks, or textured surfaces. Steer around slopes steeper than 35 degrees anywhere you expect slabs thicker than 6".

    (3/27/2023) Strong easterly winds began gusting by the summit of Lichtenburg midday Monday (5800ft).

    Photo: Irene Henninger

Avalanche Discussion

Slopes on the southern half of the compass got moist on Monday, and a few small wet loose avalanches occurred, but winds kept these aspects cool and crusty on Tuesday. Expect a round of small rollerballs and very shallow wet loose avalanches as temperatures warms, winds die down, and the sun makes a partial appearance on Wednesday. If spring-like temperatures start shifting wet activity onto the northern half of the compass, reduce your exposure to open slopes 35 degrees and steeper.

On Monday, NWAC forecasters investigated Sunday's skier-triggered avalanche on Mt Lichtenburg. You can read the original observation HERE. The skier was the second skier on the slope, and it released above him, catching himself and one other skier parked beneath him. They were partially buried but uninjured.  The stand of trees at the bottom of the relatively small slope presented a terrain trap that increased the potential consequences of the avalanche.  

 

Régions couvertes