Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

A few inches of snow will fall during the day, and the temperatures will rise. Avalanche danger will slowly increase throughout the day. Steer around steep slopes, especially as new snow amounts grow deeper and if you notice long, shooting cracks from your weight or any natural avalanche activity. 

Avalanche problems

  • Storm Slabs

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

    We're forecasted to total about 6 inches of snow from the overnight hours and through the day on Monday. Snowlines are also forecasted to rise slightly, from 3000ft to 3500ft. As new snow amounts increase towards 6 inches and temperatures go up, you may find instabilities in the new snow layer, mainly at mid and upper elevations. 

    Your largest concern is in new snow deposits. These will probably be more reactive in wind-loaded areas, but with the temperature increase, you could trigger an avalanche in non-wind-loaded areas as well. You can evaluate how well the new slabs are bonding with simple tests like slope cuts, skin track tests, and hand shears. There's a small chance that even if you trigger a small slab, it could step down to a deeper slab. As snow depths grow to 6 inches or more, if you notice red flags or have any uncertainties, avoid slopes steeper than 35°.

    Example photo: shallow slab avalanches like these may occur, especially as the day progresses, and with a human trigger. 

    Photo: Matt Primomo

  • Loose Wet

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

    Temperatures will slowly rise during the day. Moist snow and rain is expected to fall near the bottom of the lower elevation band. Dry snow will become damp, and rollerballs, possibly followed by wet loose avalanche activity, could result.  If you notice snow becoming sticky and wet, consider avoiding steep nearby slopes, as you might trigger an avalanche. If you see any wet loose avalanches running naturally, avoid traveling on and under similar steep slopes. Avalanches will probably remain small and limited to the top 6 inches or so of snow.

    Example photo: If you see rollerballs, wet loose avalanches could be triggered or may occur naturally. 

Avalanche Discussion

Over the weekend we didn't see large weather inputs, with light to moderate wind (previously strong) and only a few inches of new snow.  On Sunday backcountry users on Lichtenburg reported very small avalanches on stiff wind board. You can read their observation HERE. On Saturday, observers on Lichtenberg Mtn reported areas with significant wind-affected snow (recent east winds) were mostly difficult to trigger or crack. They also reported a zipper crust was most pronounced above 5,000ft with soft snow and good skiing below. On Friday, observers in the Skyline Lake area reported cracking in fresh wind slabs at low and middle elevations and some light rain in the afternoon. 

Stevens Pass picked up over a foot of new snow on the 17th with intense snowfall rates and periods of strong west wind. Numerous triggered and natural avalanches in the new snow were reported. It's been 10 days since some very large avalanches ran on deeper weak layers within the Solstice Crust sandwich.  Heavy snow on the 17th could have been enough to re-activate these deeper weak layers, especially in the eastern end of the zone. If you see evidence of any recent avalanches, please submit an observation. The Solstice crust is now at least 5 feet below the surface in much of the zone. The weak layers consist of faceted melt forms, and some snowpack tests have given sudden and propagating results.

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