Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

A foot or more of fresh snow should greet us by the time Wednesday rolls around. Strong west winds should create thick slabs, these could be larger and easier to trigger near ridgeline terrain. Use an assessment mindset on the tail of this prolonged stormy period, and choose your routes accordingly. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Expect you could trigger avalanches on steep slopes on Wednesday. These are most likely in steep terrain that has been drifted over by the strong westerly winds. You'll find at least a foot of fresh snow, and it's all resting on a slick ice crust. Temperature fluctuations during the snowfall may be enough to create unstable storm snow even outside of wind affected areas. In any case, look for signs of instability such as long shooting cracks, and use small test slopes to check how the new snow is bonding. Quick hand pits, shovel tilt tests, and extended column tests are also a good way to look for unstable snow.

    As the storm will be beginning to wind down on Wednesday, it won't be a bad idea to give the new snow another day to bond before stepping out onto steep slopes. 

    Glide avalanches could still occur on large, steep slopes especially those that are rock slab or grassy underneath. Beneath the new snow, you'll find a stout or breakable ice crust. Travel could be challenging on steep slopes if the new snow is shallower, and the crust refrozen.

    (12/20/2022)

    Example wind slab at Snoqualmie Pass. They could look like this tomorrow.

    Photo: WSDOT Avalanche Team

Avalanche Discussion

New snow should pile up quickly Tuesday night into Wednesday morning, and strong westerly winds will blow. Expect to find some 1.5ft or more over the "Xmas Crust". The cooling trend should help put an end to wet snow instabilities at all but the lowest elevations on Wednesday. SPMR reported a number of small wet loose slides where the 6" of new snow slid easily on a slick ice crust on Tuesday. Warming daytime temperatures helped initiate this problem. Highway 2 has been closed since the 24th due to thick freezing rain (see photo below), but may be opening soon. There may have been a round of wet slides on the 24th into the 25th, but information is limited and we are still gathering information following this long set of storms. On the 24th, WSDOT did a round of control work, and reported a number of avalanches, one of which crossed Hwy 2. That storm was a complex battle between warm, moist air and very cold air. It created a stout ice crust in many areas.

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