Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

The warmest day of the season will deliver rain to the highest peaks and create dangerous avalanche conditions on Wednesday. Avoid traveling on terrain over 35 degrees and underneath steep rocky slopes where snow could shed from above. The potential for very large avalanches should be in the front of your mind and shape your travel plans.

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    With freezing levels set to skyrocket toward 8500 feet, rain will reach the tops of all but the highest peaks of the Cascades on Tuesday night and Wednesday morning. We expect a wide range of wet avalanche problems due to this warm-up, including Wet Slabs, Wet Loose, and Glide. We have lumped them all together here into Wet Slab because these problems are often intermingled and difficult to differentiate. To further complicate the matter, precisely predicting wet avalanches is notoriously difficult since they are not well understood. Wet avalanches can occur hours or even days after water is introduced to the snowpack. Luckily, you can minimize your exposure to these erratic avalanches by choosing safe travel routes, staying off slopes over 35 degrees, and being aware of the terrain above you at all times.

    Glide avalanches and cornice collapses are the hardest of these avalanches to predict, but we feel that this will be a timeframe in which they will rear their ugly heads. Glide slopes are often smooth and you can look for crevasse-like cracks in the snow to identify potential areas of concern. The travel advice stays the same, keep aware of the terrain above you and give these slopes a wide berth by choosing safe travel routes.

    (1/11/2022)

    Multiple paths on Granite Mountain produced wet avalanches on Tuesday (1/11) as elevated freezing levels and rain impacted the zone.

    Photo: John Stimberis

Avalanche Discussion

Snoqualmie Pass is in the midst of a wet avalanche cycle. On Tuesday, WSDOT’s avalanche crew relayed information about some very large wet avalanches that released on Granite Mountain’s south face. Over at Alpental, the pro patrol reported that the snowpack is slowly starting to separate from rock walls, forming large Glide cracks. As noted above, predicting the timing of wet avalanches is almost impossible, but another night of above freezing temperatures on Tuesday and continued rain on Wednesday will only increase their likelihood. 

Lower elevations have received several rounds of rain and freezing rain since January 6th, possibly making them better suited to handle what's to come. That doesn't mean these areas are without hazard, but the main concern is upper elevations seeing rain for the first time this season. As rain falls on a cold layered snowpack overnight on Tuesday, we expect widespread wet avalanche activity that is in line with conditions for High avalanche danger. As daylight breaks and our forecast window begins on Wednesday, dangerous conditions will persist but possibly not at the same level. Make your own assessment in case the storm lingers longer into the daylight hours. Remember, unusual weather often leads to unusual avalanches and wet avalanches can occur long after the rain has stopped.

Keep in mind that recent very large avalanches up to size D4 have been reported daily since the last storm cycle on January 6-7. While we do not have enough information about these avalanches to officially call this a deep slab problem, you should shape your travel plans with these monstrous slides in mind. Uncertainty surrounding these events has us on edge during this warm spell. Slopes that did not produce very large avalanches in the last cycle may reach their tipping point due to high freezing levels, rain, a falling cornice, or a wet avalanche during this cycle. Consider avoiding open alpine slopes and large avalanche paths until this storm has played out and the snowpack has had time to adjust to this significant load.

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