Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Warm temperatures should make wet avalanches on slopes in direct sun your primary concern on Wednesday. Don't linger beneath steep rocks and cliffs where these avalanches can start. If you seek out steep shady terrain in the alpine, also be aware that you could still trigger an avalanche in older wind-drifted slabs of snow. 

Avalanche problems

  • Loose Wet

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

    This won't be the first day of sun on fresh snow for southern aspects in the East Central. However, very warm afternoon temperatures will likely break down thin surface crusts, and you will see natural wet loose avalanches run in steep terrain. Rocks and cliffs still holding snow are prime locations for these avalanches to begin, so monitor overhead terrain and don't linger under these features in the warm afternoon sun. You can also trigger these small, slow-moving avalanches that have a knack fro grabbing your feet, skis, or machine and pulling you downhill. So consider sticking to lower angle and less consequential terrain if you are traveling on sunny slopes later in the day. Wet snow surfaces, rollarballs, and snow that feels sticky are the first signs that wet loose avalanches are possible. 

    (3/25/2022) Wet loose avalanches often begin in steep rocky terrain like in this photo.

    Photo: Katie Warren

  • Wind Slabs

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

    If you seek out shadier aspects for recreation on Wednesday, you may still find lingering pockets of wind slabs. We expect most of these slabs to be small and are becoming more difficult to trigger. But a snowmobile triggered avalanche near the border of the Snoqualmie and East Central zones is bullseye information that these slabs are still a concern. So, don't let your guard down in steep terrain near ridges, rocks, cliffs, and confined features where even small avalanches could have high consequences. Cornice features, textured surfaces, and stiff snow over softer snow are all ways to identify wind slabs. Before committing to steep slopes in wind exposed areas, look for signs of instability in small test slopes, such as long shooting cracks. If you identify any signs of unstable snow, steer around these stiff pillowlike slabs or stick to lower angle and less consequential terrain. While we have had decent sunny weather for a couple of days, Wednesday will get substantially warmer, with 5000ft temperatures potentially nearing 40°F. As usual, with rapid weather changes, there is always some added uncertainty. Although we don't expect widespread cornice failures, it will be something to consider. If you observe large, overhung cornices sitting in the sun, don't linger below them and consider giving them wide margins by traveling far below them in the terrain.

    (1/21/2023)

    These cornice formations and textured surfaces are a good indication that wind slabs are present on this slope. 

    Photo: Katie Warren

Avalanche Discussion

On Tuesday, NWAC forecaster Matt Primomo got out into the Entiat River Drainage to investigate any lingering instabilities with the 1/4 surface hoar layer. He found moderate to hard, sudden small column test results on this layer below the MLK crust. Large column tests did not show signs of propagation on this layer where he traveled. That said, the MLK crust was variable in thickness, and there may still be very isolated pockets of terrain where you could trigger an avalanche on this persistent layer where the MLK crust is thinner. There have been no recent avalanches on this layer in the East Central Zone, and the last reported avalanche was last week near Stevens Pass. While it no longer warrants a specific problem in the forecast, you should still consider digging down to identify this layer if traveling in sheltered northerly aspects near and above treeline. If you find this layer well preserved under a thin MLK crust, default to low angle terrain to reduce your exposure.  

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