Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You may be able to trigger small avalanches in freshly drifted snow at the highest elevations and wet avalanches lower in the terrain. Up high, the incoming snow will be deposited by wind, while it will fall in a more liquid form at lower elevations. Watch for blowing snow and rollerballs to point you towards the danger.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Watch for triggering wet avalanches where rain falls on previously dry snow. This will be most likely at middle elevations near the pass or the Cascade crest. If you see fresh avalanches or rollerballs or find wet, weak snow, stick to slopes under 35 degrees. Avoid areas with overhead cliffs, rock features, or steep terrain. Cold temperatures in the valleys may form an ice crust, preventing rain from wetting the snow and making these avalanches less of a concern. 

    (12/31/2025)

    A natural, loose wet avalanche occurred on Lichtenberg Mtn on 12/31. Size D1.5. SSW, 5,400ft

    Photo: Phil

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    If you venture to upper elevations, watch for triggering avalanches in recently drifted snow. You may see active blowing snow pointing towards suspect leeward slopes. Steer around the freshly drifted pillows that get deposited on steep slopes. These new slabs of snow could be easily triggered as they will likely be resting on weak layers of snow.

    Above 5,500ft, you could find up to 7" of new snow and enough southwesterly wind to create a new avalanche concern. Winds may only be strong enough for new slabs on the immediate leeward sides of ridges, and not lower in the terrain.

    (12/28/2025)

    Natural wind slab avalanche in Skyline ridge area. This avalanche likely occurred on Saturday, December 28th.N, 5300ft SS-N-R1-D1-S 

Avalanche Discussion

The big question for Friday is how much precipitation will fall as snow, how much will be something else, and exactly where each will fall. It's likely that upper elevations will see snow, and that the further east you go, the less rain will fall. Freezing rain, which could quickly form a crust, is a possibility at low elevations. We'll have to see once it's on the ground.

Weak snow surfaces abound, even on southerly aspects where thin crusts formed this week. The "good," part of the rain is where it falls, it should destroy these potential weak layers. But they will likely be preserved and buried at upper elevations. Overall, cold air to the east has kept Stevens Pass cold and most snow surfaces dry. Temperature inversions are maintaining consistently cold temperatures in the valleys. Warmer temperatures at very high elevations will begin to moderate. Looking forward, we expect a slow warming trend.

Earlier this week, both sun and warming temperatures caused loose (often wet) avalanches on southerly slopes. On the 30th, an NWAC Forecaster near Lake Valhalla reported decent snow cover above 4,000ft and easterly winds transporting snow onto select favored slopes. Under the new snow, you may still find evidence of this wind-drifting at upper and middle-elevation features. It will be difficult to trigger an avalanche in these layers.

In the upper snowpack, the December 24th crust is absent above about 5,400 feet but is roughly 12 inches below the surface at lower elevations. You can find the stout December 18th crust matrix in the middle of the snowpack, 2-3 feet below the surface on most slopes. It may not exist above 6,000ft, though we don't have great data at those elevations. These crusts are good layer markers, but they aren't problematic for avalanches.

 

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