Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Tue
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 5 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Ongoing mild temperatures and strong sun will maintain a threat of wet avalanches on slopes steeper than 35 degrees. Time your travel to be off of and out from under sun-exposed slopes before the snow becomes wet and weak. Steer around wind features and drifts at upper elevations where you still may be able to trigger a large wind slab avalanche.

Problemas de aludes

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1

    Wet avalanches can develop quickly and catch you by surprise. They will first become active on the east aspects and later on the west aspects. Conditions may change dramatically through the day and as you change aspects and elevations. Plan ahead and be ready to move to more shaded aspects or slopes that are under 35 degrees. Take note of how much the surface snow has frozen or melted.  Anticipate when surfaces will become wet and weak. Move off of steep slopes before the snow is unsupportive and weak enough to entrain an avalanche.  

    Monday will be the second day in a slow and ongoing wet loose avalanche cycle. Avalanches could be large near the Cascade Crest, where more than 10" of snow may have fallen. There's still enough dry snow available to produce avalanches especially at mid to upper elevations and on the northeast and northwest aspects. Only the most northerly and shaded slopes are free from the effects of the strong April sun. 

    (4/9/2021) Widespread, large wet loose avalanches off steep southeast aspects at adjacent Stevens Pass. Similar conditions may occur this week.

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    You may be able to trigger wind slab avalanches on leeward sides of ridges where slopes are steeper than 35 degrees. While these avalanches are becoming harder to trigger, they could still be big enough to kill you. Avoid thickly loaded leeward slopes and steer around unsupported and wind-sculpted features. Other indicators of wind slab conditions are textured snow surfaces and firmer or supportive dry snow.

    Wind slabs formed through the 10th with strong west through north winds. Slabs formed on a variety of surfaces and could be up to 2 feet deep. At Snoqualmie Pass, a skier was injured on April 10th after getting caught in a wind slab avalanche that ran on a layer of weak snow. While the same weak layer hasn't been observed in this zone, it's worth keeping an eye out for it. If you travel to upper elevations, look for hard-over-soft layering about 1 foot below the snow surface on cold, shaded slopes. 

    (4/10/2021) A small wind slab avalanche triggered on an inconsequential test slope. This was on a leeward, 40 degree slope at ridgetop in the Stevens Pass zone.

Avalanche Discussion

On Sunday, observers reported numerous wet loose avalanches on steep sunny slopes. Late last week, textured and pillowed snow surfaces could be found on many upper elevation slopes, and small ski-triggered wind slabs were reported from the Chiwaukum Range. Similar conditions were reported in the Stevens Pass zone on Saturday. Storm totals since the 7th are 10-18" near the Cascade Crest.

Lower recent snow totals in eastern portions of the zone may limit avalanche hazard in areas such as the Wenatchee Mountains. The lower snowpack is generally strong and well settled, although a layer of facets associated with a crust from mid-January can be found 2-6 feet below the surface. This layer has been dormant for about a month but it may awaken later this spring with the right conditions.  

If you're out this weekend, help us keep up with the quickly changing spring conditions by submitting an observation here. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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