Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Identify areas of wind affected snow as you climb higher into exposed terrain. Consider using test slopes to check how wind slabs may react under your weight. Be careful on steep slopes and look for signs of instability such as shooting cracks. 

Problèmes avalancheux

  • Wind Slabs

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

    Look for signs of wind transported snow as you gain elevation, such as sharp drifts, small cornices, and wind rippled snow. Signs of instability often associated with wind slabs are shooting cracks and hollow, drum-sounding firm snow. If you observe any of these, steer around similar looking areas on steep slopes. You can check how the snow is reacting by using small, inconsequential test slopes before entering larger slopes. Use safe travel protocol, only exposing one person to a slope at a time, and never ride on top of other people. 

    (12/16/2021)

    Blowing snow and fresh wind drifts in the East Central Zone.

    Photo: Kyle Hornor

Avalanche Discussion

Wind was the big story on Thursday. Much of the zone picked up another few inches of very low-density snow Wednesday night, and then the winds blew. Forecaster Katie Warren reported that winds were drifting snow, and had shifted directions during the day in the Salmon la Sac drainage on Thursday. Another observer also reported that winds were drifting snow in the Chiwaukum Range. Needless to say, expect to find wind slabs in various places and elevations because of these recent winds. 

We've received a significant amount of new snow in the past week. Snow fell on various surfaces, including softer snow, wind deposited snow, and rain crusts. The snowpack depth and structure vary significantly from west to east. Near the Cascade Crest, you may find areas with up to 5 feet of snow on the ground, while further east near Mission Ridge the snowpack may be only 1-2ft deep. 

A pair of crusts from late November and December 8th may be found at higher elevations of the zone near the crest. These crusts may harbor weaker snow above them and are worth evaluating before deciding to enter more complex terrain. We do know that a deeply buried crust has created avalanches in the neighboring East North zone. You can dig down and use snowpack tests to check how snow is bonding to deeper layers.

Near Mission Ridge, you'll likely find weak snow at the ground in lieu of any crusts. An observer reported weak, faceted grains at the base of a shallow snowpack from that area on Tuesday. These 'basal facets' will be worth considering with any thickly drifted wind slabs, and as we head further into the winter.

Régions couvertes