Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
Voir sur la carte

Danger d’avalanche

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

Points saillants

Soft fluffy snow  and a potentially weak snowpack make a very nasty combination. It will be nearly impossible to manage these avalanche concerns with any level of certainty. Dial it back and stick to lower angle and treed terrain.  

Problèmes avalancheux

  • Storm Slabs

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

    There’s a LOT of new snow at the Pass. Storm totals at middle and upper elevations top 3 feet! Yes, this storm ended very cold leaving the snow mostly right-side-up. However, variations in temperature early in the storm and periods of heavy snowfall left several inter-storm layers that still could produce avalanches. Indeed, recent human triggered storm slabs have been reported.

    You’re most likely to trigger an avalanche in the recent snow in wind affected terrain, on very steep slopes, and near convex rollovers. Most of these slides should be fairly small, but they could act as a trigger for deeper avalanches. Even if you don’t trigger a slab, expect loose dry sluffs in steep terrain. Some of these slides could run far and fast.

    A small skier triggered storm slab from Saturday. Photo: Kyle Rowe

  • Persistent Slabs

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

    A recent avalanche, several audible whumpfs, numerous snowpack tests, and a well documented weak layer all point toward the potential for large difficult to predict avalanches failing in the old snow.

    Weak snow from the January draught and facets above the 1/10 crust could both be the culprit. The highly variable nature of these layers is what makes this so tricky. Even tracks on a slope don’t mean it’s safe. The only pattern seems to be these layers are much more common on shaded aspects.

    This won’t be a problem you can outsmart or figure-out. Steer away from steep open slopes. Avalanches could break widely. Recent slides took out the entire width of features.

    (2/2/2025)

    This avalanche released after a audible whumpf. The slide failed on facets over a crust and released the entire width of the feature. NE, 3700ft

    Photo: Summit at Snoqualmie Professional Patrol

Avalanche Discussion

After such a long January dry spell, it’s great to see winter back in the mountains! All the light fluffy snow is inviting and exciting. Don’t let that blind you. Sure you can find slopes that didn’t slide or tests that didn’t fail. However, there is plenty of evidence pointing toward unstable snow.

Alpental Pro Patrol heard an audible whumpf and the slope below them released during control work Sunday. This slide failed on facets over a crust (NE, 3800ft). What surprised us was how low in the terrain this slide occurred (3700ft). It adds to the evidence (collapses and snowpack tests) from the past several days. Is one avalanche a persistent slab problem? Maybe, maybe not, but it’s certainly shaping the way our team and many professionals are approaching the mountains.

Monday looks like a very cold day! Bundle up. Exceptional riding conditions have been reported in the zone. Expect deep snow in open areas and slightly scratcher conditions in the trees.

Régions couvertes