Bulletin d’avalanche

East Slopes South

Northwest Avalanche Center
Voir sur la carte

Danger d’avalanche

Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Open full map
Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A storm may bring over 1ft of snow to the East South, and new snow may not bond well with underlying surfaces, and you could easily trigger avalanches in steep terrain. Thursday will be the wrong day to travel in exposed terrain at higher elevations. Stick to lower-angle slopes in wind-sheltered areas.

 

Problèmes avalancheux

  • Storm Slabs

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

    Sunny weather, with cold clear nights, has created widely varying surfaces. Southern slopes and lower elevations have breakable melt-freeze crusts, upper elevations have wind-stiffened surfaces, and northern sheltered aspects have soft, weakening storm snow. Large, feathery surface hoar crystal now overlays these surfaces. New storm slabs that form on top of surface hoar on a crust could be touchy and propagate widely. Avalanches in areas where the wind has drifted snow deeper could be large and dangerous. These variable old snow surfaces often lead to a widely variably bond with the new snow, and it will be essential to assess how the new snow is bonding to the old snow surface. Thursday will be a good day to observe how the new snow reacts while sticking to travel on lower-angle terrain sheltered from the wind. Use small test slopes and hand pits to gauge how easily the new snow slides. Look for red flag signs of instability, such as recent avalanches or cracks shooting out from your feet or sled. 

    (12/20/2022)

    Small test slopes like these are a great way to see how new snow bonds with underlying surfaces. If you see small avalanches like this, avoid steep slopes. 

    Photo: Public Observation

Avalanche Discussion

This is an unusual storm pattern, and there is some uncertainty regarding the amount of snow expected. If more snow than anticipated accumulates on these weak surfaces, natural avalanches may become more likely. While winds will not be very strong, they will be in transport range, and it will be pertinent to avoid steep wind affected terrain where avalanches could be larger and more dangerous. 

Temperatures and snow levels will increase during the day on Thursday, and at lower elevation trailheads, you may also see some wet loose avalanches in steep terrain. Looks for signs, such as rollerballs or rain on dry snow, to indicate wet loose avalanches are possible. Avoid steep terrain where you find wet, heavy snow conditions. 

On Saturday, I traveled into the Ahtanum Meadows area and found approximately 7 inches of new snow over the Christmas Crust at lower elevations and nearly 2 ft at higher elevations.  

If you get out into the East-South, let us know what you see by submitting a public observation. 

Régions couvertes