Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

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

Although you could travel on many slopes and not trigger an avalanche, riders have triggered isolated but large and surprising slabs in steep terrain due to slow bonding with old weak layers. You're not likely to get direct signs of instability first, so use terrain to your advantage and stay away from unsupported or highly consequential slopes near and above treeline. Snow surfaces may become moist on all aspects, and you could trigger wet loose slides on steep slopes. 

Avalanche problems

  • Loose Wet

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

    Warming temperatures are expected to moisten snow surfaces on all aspects. Northerly aspects hold dry snow, but may become moist and sticky enough to entrain at mid and lower elevations on Sunday. If you see rollerballs or moist snow surfaces, consider moving to lower-angled slopes. You could initiate 'pushalanches' on steep slopes, and these could pack an unwelcome punch if you got caught. Look for clues like rollerballs, and fresh fan shaped slides during the day. 

    Upper elevation, shaded slopes are likely to remain dry during the day. Continue to check for cracking or shooting cracks that could indicate isolated wind slab danger at the higher elevations and in very steep extreme terrain.

    (2/10/2023)

    Loose wet avalanches in steep, rocky terrain just west of Skyline road.

    Photo: Matt Primomo

  • Persistent Slabs

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

    Chances remain to trigger large slab avalanches up to a couple feet deep. We're at the point when you're not likely to get direct signs of instability before triggering a slide, but if you did it could be surprising and consequential. You may be most likely to trigger a slab in obviously wind loaded areas, but they could also happen on steep unsupported slopes that aren't heavily affected by wind. Weak snow from early February, and above a slick crust from Martin Luther King weekend has been slow to heal with the newer snow load on top.

    Use well supported terrain, make sure to practice safe travel techniques, and expose only one person at a time to the hazard. 

    (2/11/2023)

    Full propagation ( ECTP22) on a layer of 1mm rounding facets sitting on a crust. Joe found this layer 17 inches below the snow surface on a ESE aspect at 5,400ft on Dirtyface.

Avalanche Discussion

On Saturday, a report came in of a large ski triggered slab on a northeast aspect at around 5,400ft near Lake Josephine. The folks involved were reported to be banged up, but ok after one may have gotten pushed up against a tree. The slide was about 24" deep. Another ski triggered slide occurred on the 9th from very steep terrain near a ridgeline. In any case, these incidents speak to continued instabilities with the newer snow and older weak layers. Saturday was a beautiful day, and many folks got out to enjoy the good snow and nice weather. Observers noted a round of near surface faceting and surface hoar growth on many aspects at mid and upper elevations near the pass and further east. 

Avalanche danger is expected to increase substantially overnight into Monday morning with an incoming winter storm. You could expect to find around 2ft of new storm snow from the past week. A fairly widespread storm slab cycle occurred with a burst of heavier snowfall and strong winds in the morning of the 8th. This day was very active, and control work at the ski area that day produced widespread storm slab results, 3 were reported to have run down to the MLK crust. Observers also reported large, natural slab avalanches on steep, leeward slopes, just below ridges that saw wind loading including Windy Ridge and the Rooster Comb, above Lake Susan Jane. A couple of these also were suspected to have run on the MLK crust as well. Riders triggered a smaller slab avalanche In steep rocky terrain in Lanham Creek and on a ridge just outside of the Stevens Pass Resort boundary in Hollywood bowl, SE, 5,200ft. 

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