Bulletin d’avalanche

Stevens Pass

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

On Friday, conditions will remain dangerous in the Stevens Pass zone even though the snowfall will taper. You can trigger avalanches in recent snow on slopes steeper than 35 degrees. Minimize the risk of getting caught in an avalanche by sticking to lower-angle terrain and avoiding steep roll-overs and slopes above rocks or cliffs. 

Problèmes avalancheux

  • Storm Slabs

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

    To safely travel in the backcountry, stick to well-supported lower-angle slopes. Steer around typical trigger points like convexities, and unsupported, "hanging" features. Stay off of steep, leeward sides of ridges where the wind may have formed deeper drifts.

    Watch for cracks shooting through the snow and recent avalanches to indicate the danger. Use small features and quick tests to see how easily the snow slides before getting onto bigger slopes. While less likely, you could trigger much deeper avalanches on a storm layer from the beginning of the week. Dig down about 2 feet and use snowpack tests to locate this layer, just above a crust. 

    (12/26/2024)

    The crown of a skier triggered avalanche that ran in the new snow. Big Chief Mtn, SE, 5,200ft

Avalanche Discussion

An intense and prolonged storm moved into the region on Wednesday, and it delivered over 19" of snow and 2" of water equivalent at the time of publishing. On Thursday, observers reported widespread triggered slab avalanches in the new snow, with many big enough to bury a person (size D2). Steves Pass Patrol reported very reactive conditions with avalanche control. In areas that hadn't received skier traffic or control work in the past week, avalanches involved storm snow from earlier this week. 

All the weight of the new snow could cause avalanches to break on a recently buried weak layer, over 2 feet below the surface and just above a thick series of crusts. Observers on Monday and Tuesday reported triggering avalanches on a storm interface buried on the 22nd.  One avalanche 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 reported avalanches in wind-sheltered terrain. They found lingering instabilities in snowpack tests on the 12/22 interface that matched the recent avalanches. While mostly the interface consists of stellars (snowflakes) some profiles have revealed small faceted grains.

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

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