Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The first big winter storm of the season will result in very dangerous avalanche conditions on Saturday. Expect natural and human-triggered slides to occur throughout the weekend. This is not the time to enter avalanche terrain and ruin your season before it begins. 

Problemi valanghivi

  • Storm Slabs

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

    Expect multiple feet of new snow, strong winds, and fluctuating freezing levels to combine with an existing weak snowpack to create Storm Slabs at Snoqualmie Pass on Saturday. You are very likely to trigger avalanches on slopes over 35 degrees and natural avalanche activity is expected, particularly in the morning hours. In isolated areas, avalanches could involve much of the snow received so far this season. Travel in avalanche terrain is not recommended at this time.

    (12/1/2023)

    Example: The crown of a small, natural, storm slab avalanche in the neighboring Stevens Pass zone. This occurred in only 6-8" of new snow and the 11/30 interface was very reactive. 

    Photo: Matt Primomo

Avalanche Discussion

What a first day for me to begin forecasting. Winter enthusiasts have been waiting for this storm to kick off the season. Now that it’s here, I have to break the news to you that travel in the mountains is not recommended on Saturday due to very dangerous avalanche conditions. This includes closed ski areas where avalanche mitigation is not currently taking place.

The calendar has just flipped to December so information is extremely limited, leading to plenty of uncertainty. We do know that at mid to upper elevations snow has been falling on predominantly a melt-freeze crust, creating the 11/30 interface. In these elevation bands, a poor snowpack structure and pockets of weak surface hoar were identified by both Alpental Pro Patrol and an NWAC forecaster. These could result in some surprising avalanches. At lower elevations, new snow has been falling on essentially bare ground. As of Friday evening, our storm total is at 7 inches. We’re expected to have multiple feet over the 11/30 by the time we reach Saturday evening. 

Even with the new snow, natural hazards such as boulders, shrubs, open creeks, and holes will still exist. Because of them, getting caught in an avalanche, regardless of its size, could be consequential. Try to temper your excitement and show some restraint. Many avalanche accidents occur in the early season when snowpacks and intimate knowledge of them are thin.

Regioni coperte