Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Dangerous avalanche conditions will exist in the mountains on Tuesday.  Slopes are now primed for human-triggered avalanches, so stick to slopes under 30 degrees as you gather information about how the snowpack has changed. Don't be surprised to see natural avalanches during periods of heavy snow or strong winds. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    The snowpack will be a lot different on Tuesday from what you may have seen recently. Slab avalanches are now the primary concern as continued precipitation, wind, and a warming trend transform our snowpack. Digging with your hands or shovel to identify heavy snow over weak snow or areas of poor bonding will be necessary. Small test slopes can give you some information about how the recent storm snow is reacting to your weight. Be leery if the new snow forms a cohesive slab or if blocks of snow are failing in your tests. Any slabs should grow in size as you ascend in elevation, particularly in areas that are prone to wind. Slabs in wind-prone areas could be several feet deep and much firmer than the surrounding snow, possibly feeling hollow. Regardless of if the slab is composed of storm snow or thickened by the wind, you should avoid slopes over 30 degrees if you notice failures in your tests or see red flag signs of instability such as shooting cracks or whumpfing collapses. 

    There is still the possibility of surprising avalanches that wrap around terrain features or propagate widely, even in areas often considered as “safe”, such as treed areas. If you notice any avalanches acting in this way, you should dial back your terrain choices even more.

    (1/2/2022)

    Shooting cracks and whumpfing collapses were observed at Snoqualmie Pass as a storm approached and stiffened snow surfaces on 1/2/22. These are red flag signs of instability and should drive you to lower angled terrain.

    Photo: Robin Pendery

Avalanche Discussion

Observations from the pass were limited due to the road closure and power outage that affected the area on Monday. The WSDOT avalanche crew reported 19” of snow had fallen overnight on Sunday and that multiple natural avalanches had occurred. Locals who had the time for some small ski tours around the Summit at Snoqualmie indicated that small human-triggered avalanches were occurring in the new storm snow. This is a continuation of observations we received as the storm began on Sunday and the snowpack started to change. We expect this pattern to continue and for human-triggered avalanches to be widespread on Tuesday. The snowpack has changed dramatically from what we have seen over the past two weeks, and this may just the beginning of the transformation that will occur over the next few days.

On Tuesday, the natural cycle may subside, but that doesn’t mean that natural avalanches can’t happen. Many slopes may not have reached their tipping point and could during periods of heavy precipitation or strong winds. With close to 2 feet of new snow on top of the ~3 feet of snow we previously had sitting on the Solstice Crust, the potential for large and dangerous avalanches is very real and you should manage terrain carefully. 

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