Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Keep an eye on how dynamic springtime weather is changing the snow surface throughout the day. If you find that the snow has become wet and sticky, you should start to think about wet avalanches on steep slopes over 35 degrees.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Wet Loose avalanches could occur on steep slopes over 35 degrees wherever the snow surface is heavy and wet on Thursday. This could be more likely as the day wears on and warm temperatures destabilize the snow surface. Wet Loose avalanches often start at a point and fan out as they descend downhill, entraining additional snow or even triggering slabs. Visual clues such as fresh rollerballs and pinwheels are precursors to wet avalanches and can help you know that slopes may be reaching their tipping point. You can also take a moment to step into the snow and see if you are plunging in past your ankle to let you know that the snow is reaching the threshold for producing these slides. If you find that these conditions have been met, avoid open slopes over 35 degrees.

    (4/4/2021) Example: Take the time to step off your mode of travel and see how deeply you are sinking into the moist snow. If you're sinking in deeper than your ankle, you should start to suspect wet avalanches.

    Photo: Andy Harrington

Avalanche Discussion

Wednesday night’s cool temperatures should freeze the surface of our wet snowpack for the first time in a few days. This will help to stabilize the snow and limit avalanche activity first thing in the morning on Thursday. Surface conditions should soften as freezing levels are expected to rebound and reach the 7000 foot range by the afternoon. This surge will reinvigorate concerns for wet avalanches across the zone, particularly at upper elevations where a few inches of new snow may have fallen Wednesday evening.  This includes concerns for cornices collapsing and Glide avalanches on smooth rocky slopes. Be sure to give these overhead hazards plenty of space as you travel, they're unpredictable and erratic.

The upper snowpack around the pass is generally saturated due to warm and wet springtime weather in recent days. NWAC weather stations have shown impressive settlement rates since our most recent storm over the weekend, showing that the snowpack should be gaining strength. That said, the recent stormy weather resulted in both dry and wet natural avalanche cycles in the zone, some of which failed on weak layers of graupel. Apart from the recent storm snow and surface conditions, we are continuing to watch a weak layer of snow just above the Early March Crust, which can be found about 3 feet below the surface. There has only been one confirmed avalanche on this layer at Snoqualmie Pass and it was almost a week ago (3/18). Look for this weak snow on NE-N-NW aspects at mid to upper elevations and consider the consequences of a deeper slide before stepping into terrain on these slopes.

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