Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

A big, messy change in the weather could create a complex and dynamic set of avalanche concerns on Friday. This might include natural avalanches. Give yourself plenty of options to adapt to the changing conditions.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    You could trigger avalanches within or at the base (1/16 interface) of the storm snow. These slabs should be the most reactive first thing in the morning after we get even more snow Thursday night. In some places, the new snow sits on top of weak facets and could fail easily or even trigger remotely. 

    Hand pits, small slopes, and uptrack tests can all give you a good handle on how the new snow may fail. Just make sure you’re looking all the way down (1-2ft, 30-60cm) to the 1/16 interface. If temperatures warm, it could change the way these slabs react in the afternoon.

    A storm slab that faild on the 1/16 interface on Wednesday. (1/17/2024) Photo: Nathan Yuhl

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    You’re most likely to see wet avalanche concerns later in the day and west of the Pass. However, warmer air could shove its way into the core of the zone. As it does so, avalanche concerns will shift from dry to wet. Warm temperatures and rain on snow may just result in a few rollerballs, or it could trigger a barrage of wet loose avalanches. Honestly, it’s hard to say. 

    If you notice it getting warm and muggy, see rollerballs, or find teardrop piles of debris, it’s time to start stepping back. Keep an eye on the slopes above you, and minimize any time you spend under steep terrain.

    (1/4/2024)

    Example: Wet avalanches like this could entrain the recent snow and grow larger. 

    Photo: Alpental Pro Patrol

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    The big change in the weather only adds another layer of uncertainty to this problem. Weak facets still linger 3-4ft (1m) below the surface. We’ve found them everywhere we look, and they routinely fail suddenly in tests. Smaller avalanches, failing cornices, or hitting the wrong spot could awaken this beast. Even though the likelihood is much lower, the uncertainty and consequences are quite high. Take the time to discuss this persistent issue before stepping into bigger terrain.

    (1/10/2024)

    This very large avalanche released using explosives during avalanche control at Alpental. It is an indication that deeply buried weak layers could still be active. 

    Photo: Alpental Ski Patrol

Avalanche Discussion

There’s an old avalanche adage, “Big changes mean big problems.” Snow levels should swing from near sea level to 7000ft in a 24hr period (by Friday afternoon)! That’s huge! Easterly flow could hold the warmer temperatures at bay near the Pass, but temperatures may also sky rocket. Then throw in the potential for freezing rain, sleet, snow, and rain into the mix…. The only way we can describe this is messy. Things could come unglued, or a layer of ice could all but eliminate the avalanche hazard. 

We don't often issue 3 problems in a forecast. When uncertainty goes up, terrain goes down. With so many potential weather outcomes, this will be a day to have lots of options with easy, safe routes back to the trailhead.

Regions covered