Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
Voir sur la carte

Danger d’avalanche

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

Points saillants

A welcome round of new snow comes with strong winds into Friday. Expect you could trigger shallow wind slabs near and above treeline. Theres a chance slides could be larger if they run on a recent slick crust.

Problèmes avalancheux

  • Wind Slabs

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

    6-10" of new snow combined with moderate to strong winds should create fresh, reactive slabs. The drifts may be thicker, and slabs could be larger at higher elevations. Slabs could break on a newly formed crust from previous days of warm temperatures, and theres also a chance that avalanches break about a foot deeper, on the slick MLK crust. Be especially cautious near ridges, on open steep slopes, and convex rollers that could serve as likely trigger points. You can identify slabs through textured surfaces, and stiffer snow. With these, look for signs of instability as you travel such as long shooting cracks, and consider using small test slopes to gain more information on how the snow is reacting. If you observe signs of unstable snow, steer steeper or more consequential features.

    With fairly warm and humid conditions, be aware of the potential for wet loose avalanches at lower elevations. Look for rollerballs and sticky snow to clue you into these. 

    Example human triggered wind slab off a steep ridgeline in the near treeline zone.

    Photo: NWAC Public Obs

Avalanche Discussion

Expect a snowy day on Friday. The new snow will be burying a typical mixed bag of old snow surfaces, most of which will be refreezing crust. Some weak snow may survive to get buried on shaded and sheltered terrain near and above treeline.  On Wednesday we received a report of a ski triggered D1.5 slab that ran on the MLK crust on Wednesday. It wasn't a wet slab, though warming temperatures likely played a role. Direct south facing slopes reportedly warmed up some, and there may have been a few small wet loose slides on the usual slopes of Lichtenberg. The day seemed like a battle between warm temperatures and clouds, and the warming trend is expected to continue through the night. Thursday could be downright balmy. Later in the day, winds may begin to transport snow on higher peaks.

Avalanches on persistent weak layers beneath the MLK crust are unlikely, though we've been tracking a layer of buried surface hoar from January 4. This can sometimes be found about 1-2 feet below the surface and between 5,800-6,500ft in wind sheltered terrain. On the 19th, skiers triggered a large avalanche 1-2 feet deep on Jim Hill on a NE aspect at 6,200ft. While you can find this layer in a few other locations, it's otherwise been inactive and patchy in distribution within the zone. In the neighboring East Central zone, there have been multiple observations, including large natural avalanches running on this layer. 

Régions couvertes