Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
Voir sur la carte

Danger d’avalanche

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

Points saillants

Anticipate an increase in warming-related avalanches after a long period of Low danger, especially at mid and upper elevations. Don't linger under steep slopes or cliffs where you see bulging or wrinkled-looking snow, glide cracks, or unstable-looking slabs or blocks of snow. Prepare for challenging travel conditions on variable snow and slick crusts. 

Problèmes avalancheux

  • Glide Cracks

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1.5–2.5

    Glide avalanches are not the kind of avalanches people trigger. They occur naturally when the interface between snow and the ground below becomes “slippery”, often during periods of warmer temperatures. Danger from this round of glide avalanches will be greater on slopes below rocky, snow-covered terrain, generally on aspects seeing direct sun.  Slopes with smooth ground cover are also more suspect. It's less likely, but glide avalanches could release in shaded terrain as well.

    It’s nearly impossible to forecast when they will release, so limiting exposure to the problem is the primary way to reduce risk. Cornices and other delicately perched snow features could also fail during prolonged warming.  Avoid travel - or at least move swiftly -  below glide cracks or other signs of glide.

    (2/11/2021)

    An example of glide cracks developing over a smooth rock slab in West Central. 

    Photo: Irene Henninger

Avalanche Discussion

Loose wet avalanches should also be on your list of hazards, especially in upper-elevation areas that haven’t yet produced many of them. Avoid travel on or directly below sunny slopes where you see fresh rollerballs, small wet avalanches, or simply find wet mushy snow.

No wind slabs big enough to be considered dangerous were found over the weekend. You may find bigger ones as you climb into exposed, alpine terrain. Keep an eye out for pockets of smooth-looking wind slabs and assess for instability before moving into steep slopes with consequences like rocks, cliffs, or crevasses in the runout below.

Snow surfaces vary widely between slick crust, wind-affected snow, heavily tracked-out slopes, and even some soft snow in shaded and sheltered terrain. Southerly slopes should warm enough over the next few days to produce early-stage corn conditions.  Expect firm crust on these aspects in the morning after clear skies and cooling overnight.

The distribution of weak snow at the surface should shift this week with sunny aspects melting down but shaded slopes preserving surface hoar and faceted snow that has developed over the past few weeks. Plenty of faceted snow can be found below the surface on all aspects, often sandwiched between and around crust layers. 

Régions couvertes