Bulletin d’avalanche

East Slopes South

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

On Sunday steer around pockets of wind-drifted snow at mid and upper elevations. These wind drifted pockets will likely be larger and more reactive in the western parts of the zone that received more than 6 inches of new snow. Expect small wet loose slides to become possible on steep solar aspects during sunnier periods. 

Problèmes avalancheux

  • Wind Slabs

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

    Recent new snow and steady wind seeds will keep wind slabs on the menu on Sunday. You may find these wind slabs to be larger and more reactive in the western parts of the zone (places like Mt Aix/Bumping Lake area) that received greater than 6 inches of new snow. 

    You’ll typically find wind drifted slabs on the leeward side of ridges, below cornices, or under cliff & rock bands. Using visual clues such as blowing snow or looking for wind textured slabs will help you identify slopes of concern. Shooting cracks under your machine or feet are obvious signs of instability. You can simply avoid this problem by sticking to scoured aspects or staying on more sheltered slopes out of the wind zone.

    Steer around pockets of drifted snow that appear textured or 'fat' like in this photo. 

    Photo: Joe Dellaporta

  • Loose Wet

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

    The sun may make an appearance, so this may set the stage for a round of small wet loose avalanches on steep solar slopes. Look for rollerballs and pinwheels as warning signs telling you the snow surface is becoming wet and weak. Consider moving off of steep sunny aspects if you notice the surface snow getting moist.

    (3/18/2023)

    Wet Loose avalanche on a steep sunny slope. Note how it originated at a point, near trees and rocks.

    Photo: Dallas Glass

Avalanche Discussion

The East South did pretty well out of this system. You’ll find the most new snow in the Bumping Lake area (9 inches) and lesser amounts the further east you move. Green Lake near Darland Mtn still managed to pick up a solid 6 inches of new snow. This new snow is now likely sitting on a crust on most aspects below 6000 ft. Above this, new snow may have fallen on cold, faceting snow on shaded aspects or firm crusty surfaces. As you move through the mountain use small test slopes or hand pits to see how the new snow is bonding with these old snow surfaces. Reports from the north and west have confirmed recent avalanche activity at this new/old interface, so you may find similar reactivity in areas that recieved greater than 6 inches of snow. 

At mid and upper elevations, a deep and layered winter snowpack exists. If you dig down, you will find older layers of melt-freeze crusts from around Christmas, MLK, and Valentine's day. These layers are not a concern for avalanches at this time but are a reminder that we have not transitioned to a spring snowpack quite yet. For more information about the deeper snowpack, check out Katie’s observation from Ahtanum Meadows this past week.

 

 

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