Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

As the skies clear and the sun comes out, don’t forget about Monday’s storm. Very strong winds formed unstable slabs that you can still trigger. Steer around steep slopes where you find drifted snow or notice sharp cornices.

Problèmes avalancheux

  • Wind Slabs

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

    Very strong winds during the recent storm likely formed new and reactive slabs in several areas. You can find wind loaded slopes well below ridgeline, along the sides of gullies, and on exposed slopes at any elevation. As a result, you’ll need to keep a sharp eye out for signs of wind transported snow such as textured surfaces, drifts behind objects, and firm hollow sounding snow. Stay off of slopes greater than 35 degrees where you suspect the wind deposited snow. As you ascend in elevation wind slabs may become larger and more prevalent.

    (11/27/2020) Cornices and drifts behind trees are clear indicators of wind loading on nearby slopes.

Avalanche Discussion

Six to eight inches of snow now rests on a new interface (11/30). In some areas, this may make avalanches easier to trigger. On steep sunny slopes, a firm crust formed last week. We don’t know how the new snow bonded to this crust. Conversely, in shaded and more sheltered spots, surface hoar was reported Sunday afternoon in neighboring areas near the east side of the zone. Buried surface hoar can be tricky to manage. If you see shooting cracks or hear whumpfs, dial back your terrain choices and stay out of avalanche terrain.

You could encounter locally higher avalanche danger in the northern part of the zone. Radar returns Monday evening suggests a Puget Sound Convergence Zone depositing more snow near and north of Nason Ridge, allowing for larger avalanches. 

Tuesday is a transition day, meaning the weather will transition from the recent storm to clear, sunny, and warm. Often transition days can be tricky to forecast due to competing variables and limited information. If the warming weather and sunnier skies control the day, you could see a few rollerballs or small loose avalanches in very steep terrain where unconsolidated snow escaped the wind. 

While the snowpack around the Pass is impressive for the beginning of December (40-60”/105-150cm), plenty of early-season obstacles still exist. Watch for open creeks, buried logs, and numerous small trees that may block your path.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Régions couvertes