Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

You could trigger large old wind slabs in big, steep starting zones above 5,500ft, and smaller ones due to increasing winds later in the day. Warming snow surfaces in the sun may cause small wet loose slides to run on steep slopes. Look and feel for signs of wind textured or wind stiffened snow, and identify areas you'll want to avoid.

Avalanche problems

  • Wind Slabs

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

    Wind slabs could take on various forms on Wednesday. They could be small and soft, or they could be large enough to bury or kill you. Later in the day, winds should begin drifting snow at ridgelines and may create shallow soft slabs. In some isolated areas, you could trigger a larger and more surprising slab on a weak crust from Valentines Day. Look for drifts as you gain elevation near exposed areas, below large rock outrops, and near cornices. Hedge your bets by steering clear of large starting zones that are unsupported or with unfavorable consequences.  Identify obviously wind-loaded or wind textured terrain of concern.  

    You can use small test slopes and quick, informal tests to see how the snow reacts. Look for strong over weak structure, and travel accordingly.

    (2/27/2023)

    Shooting crack in wind affected snow near Fortune Pass.

    Photo: Katie Warren

  • Loose Wet

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

    Small loose wet slides may become commonplace on steep slopes that catch direct sun. Look for signs of moistening snow, snow falling from trees and cliffs, rollerballs, and fresh fan shaped slides.  These could run a respectable distance because they'll slide on a recent crust. The debris could entrain a fair amount of snow and create debris piles that you won't want to get caught in. Especially be careful of larger terrain like rock lined couloirs, gullies and similar places where debris piles up deeply.

    (2/28/2023)

    Small solar induced loose slides.

    Photo: Matt Primomo

Avalanche Discussion

I made it up to the Icicle drainge on Tuesday, and found that the sun was warming the snow surfaces within only an hour or two of sun hit. Small sun induced loose slides ran from steep, rocky areas. Moderate but somewhat intermittent wind drifting was observed near ridgelines of the higher peaks in the range. Slopes had wind textured snow beginning in the near treeline band, and more above treeline. The crust from Valentines day was down about a foot, and another crust was down closer to 1.5 feet. Both presented with weak snow beneth them, and with sudden collapse failures with a compression test.

Forecaster Katie Warren was in the upper N Fork of the Teanaway on Monday and reported about a foot of new snow since the 25th. Snow was generally well bonded to this interface, but would fail in tilt tests. An observer reported very deep snow on the north side of Mt Howard on Monday as well.

You can find 1-3ft of newer snow from the past week sitting over a crust from Valentines Day, which often presents as a crust/facet sandwich, with weaker snow beneath the upper crust. Over the weekend, observers reported some whumphing collapses and propagating test results this crust in the mid-Icicle drainage. We've seen minimal actual avalanche activity on this layer, but continue to monitor it as snow adds up. If you get out into the mountains, submit an observation to share what you found.

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