Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Wednesday will bring quieter weather before a multi-day storm begins overnight. You can trigger avalanches about 1 foot deep in the recent snow both where the wind forms drifts and in wind-sheltered terrain. Expect a dramatic increase in avalanche danger overnight and into Thursday.

Problèmes avalancheux

  • Storm Slabs

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

    Use caution on slopes steeper than 35 degrees and steer around convex roll-overs and unsupported slopes. Be extra cautious along ridgelines and leeward slopes where you see deeper drifts or blowing snow.  East wind may become strong enough to form fresh wind-drifted slabs as the day progresses.

    Storm slab avalanches in wind-sheltered terrain might be smaller but could easily cause injuries. You can find an interface a couple of days old about a foot below the surface and just above a crust that could break easily. You can use quick tests, and small test slopes to see if this interface breaks. If you find easy, clean, failures, choose well-supported slopes under 35 degrees.

     

    (12/24/2024)

    Intentionally triggered storm slab on a steep convex roll in the Stevens Pass Backcountry. 

    SS-AS-R2-D1-I

     

    Photo: Katie Warren

Avalanche Discussion

Expect an intense and prolonged storm to impact the area starting Wednesday night. It will likely last well into the weekend and could bring very dangerous avalanche conditions.

Observers on Monday and Tuesday reported triggering avalanches on a storm interface buried on the 22nd. Skiers triggered larger avalanches in wind-loaded terrain.  One on the Rooster Comb, outside Stevens Pass Ski area, gouged deeper and ran on the Solstice crust. Another avalanche near the summit of Lichtenberg Mountain, propagated around a rock feature.

NWAC Forecasters in the Lake Susan Jane and Lake Valhalla also reported avalanches in wind-sheltered terrain. Additionally, they found increasing new snow amounts with higher elevations and lingering instabilities on the 12/22 interface that matched the recent avalanches. This interface is about 1 foot below the surface, at the boundary of two dry storm layers. It may show up as easy, planar results in snowpack tests.  Solstice crust is another 4-6 inches deeper or about 1.5 feet below the surface.

If you're in the mountains, let us know what you see by submitting an observation.

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