Bulletin d’avalanche

East Slopes South

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 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A significant storm will load cold, low-density snow onto very shallow snowpacks or directly on bare ground. It will be easy to trigger an avalanche in the wind-loaded pockets with enough snow to ride.  Any avalanche will rake you through shallowly buried rocks and stumps, causing significant trauma.

Problèmes avalancheux

  • Wind Slabs

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

    A major winter storm will bring 8"-18" of low-density snow along with moderate and shifting winds. The brunt of the storm arrives Tuesday night into early Wednesday with lighter snow or showers by the afternoon. Wind loading should bring previously very shallow snowpacks to the threshold for avalanche activity on wind-loaded terrain features near and above treeline. These same features will likely have the only terrain potentially deep enough to ride. Don't let your eagerness to enjoy the new snow tempt you onto a heavily wind-loaded slope steeper than 35 degrees where you could trigger a potentially large avalanche. Active snow transport, shooting cracks, or firm/punchy layering should all remind you to avoid the wind-loaded pockets in question. Keep in mind that any avalanche will be consequential in these early-season conditions. Most other areas including lower elevations have very shallow snowpacks with little in the way of avalanche concern.

    Example: Wind-drifted pockets of firm or textured snow where you can trigger an avalanche on Wednesday.

    Photo: Joe Dellaporta

Avalanche Discussion

Continued cold weather adds to the list of factors to plan for, which should include early-season travel conditions and wind slabs coinciding with the slopes you were hoping to ride on Wednesday. It will still be blowing and storming when you start your day with temperatures in the teens rising into the mid-20s. Bring and wear extra layers and consider wearing a buff or facemask to cover exposed skin. 

If you do head out, we'd love to hear whether Tuesday's low-density snow has formed a weak layer under the weight of the current storm snow. Such a weak layer could cause slabs to propagate more widely across terrain features.

Access to many areas of the eastern Cascades is challenging, and we have limited information about the snowpack. If you are headed out into the mountains this weekend, be prepared for long approaches with the new snow lying on nearly bare ground. Many motorized trailheads have limited snowpacks, and most have yet to begin grooming operations. New snow may shallowly bury rocks, stumps, creeks, or other hazards at any elevation. 

If you are out and about in the mountains, let us know what you find by submitting an observation.

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