Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

7a Update- More snow than previously forecasted for the Wenatchee Mountains and areas surrounding Leavenworth like the Icicle Creek drainage. Expect dangerous conditions at where it will be easy to trigger avalanches in freshly formed drifts. Stay off of steep slopes on leeward sides of ridges where you find fresh drifts and pillows of snow. You may be able to trigger wet avalanches below treeline. Watch for recent avalanches, blowing snow, and rain on previously dry snow as indicators.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    The avalanche danger will increase as wind-drifted slabs continue to build throughout the day. Watch for blowing snow and cracking in the snow to indicate which slopes will be prone to avalanches. Steer around pillows, and convexities on leeward slopes and just below ridges. You may be able to trigger avalanches easily on northerly aspects and at upper elevations. Cooler temperatures and shade may have formed a weak layer over a slick crust at the new/old snow interface. Use quick tests and dig just below the surface to look for this weak layer.

    (4/1/2023)

    A small, human triggered wind slab at Mission Ridge on Saturday.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    You could trigger wet avalanches and they may even run naturally as skies clear in the second half of the day. Expect wet avalanches primarily below treeline on shaded northerly aspects and on steep sunny, slopes if skies clear in the afternoon. On northerly aspects, they could gouge into older snow. There's uncertainty about how widespread these avalanches will be. Pay attention to how much the surface snow is moistening and how easily it slides on test slopes. Be ready to move to lower-angle slopes, if you find wet snow that slides easily enough to produce sizeable avalanches. 

    (3/18/2023)

    Rollerballs on steep slopes like this are an indication wet loose avalanches are possible. 

    Photo: Pat Riffie

Avalanche Discussion

A warm and windy storm weather is impacting the area. We anticipate that areas in the central part of the zone like the Wenatchee Mountains, the Icicle Creek drainage, and the Chiwaukum Mountains could receive higher precipitation totals and could see more elevated avalanche danger. In other areas of the zone, you may see minimal avalanche hazard and particularly less wind slab avalanche development. While we're now well into April, the avalanche conditions and snowpack are closer to that which we typically see in mid to late winter. Much of the snowpack is nowhere near transitioning to typical spring melt-freeze conditions.On Wednesday, Katie Warren went to Blewett Pass and found variable snow surfaces and a relatively cold, dry snowpack. Lower trailheads are melting out, and bare patches exist on some groomed trails, all signs that spring is near. But these recent late-season storms tend to bring complex and overlapping avalanche problems. You may experience dry snow and then a rapid transition to wet snow avalanche problems with even a brief period of sunshine. The rapidly changing weather often makes for a tricky avalanche forecast. Stay tuned to the changing snowpack conditions and look for signs of instability. Recent avalanches, rapidly melting snow surfaces, shooting cracks, or actively drifting snow are all signs of deteriorating snow stability. Monitor the snow as you travel and be prepared with options to travel on less consequential terrain with lower angle slopes if you find questionable snowpack conditions. 

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