Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Dangerous conditions should continue through Thursday after a day of heavy rain. Very large wet avalanches could run on old crust and facet layers 2-4ft deep, or on the ground. Stay off of, and out from under steep slopes until the snowpack has a chance to refreeze. 

Problemas de aludes

  • Wet Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–3

    A prolonged period of warm and wet weather, combined with a weak snowpack structure have created unique conditions for scary wet slab avalanches. These are running on old faceted and crust layers from December, and/or on the ground. What does this mean? It means slides may fracture across terrain features, and carry the entire seasons snowpack with it. Slides may be 2-4ft deep, and could be powerful enough to take out trees. Many avalanches have run on the ground, leaving a mud scar in their wake . Along with these nasty slides, wet loose avalanches may run and scour to the ground, and cornices could break away.

    Stay off of, and out from underneath steep slopes on Thursday.

    (1/28/2024)

    Very Large wet avalanche that ran naturally on 1/28 in the Icicle River Drainage.

    Photo: Erik Soldenwagner

  • Glide Cracks

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    Water is running through and underneath the snowpack. Glide activity has increased over the past 48 hours, and may pick continue through Thursday. These types of avalanches are not something we talk about too much in this zone, but with these conditions we're seeing them. Typically glide slabs run on smooth bedsurfaces, like rocks and grass. Glides could entrain more wet snow and entrain to become larger avalanches. Large, complex terrain features in the lower river valleys tend to funnel slides into gullies, and create deeper debris piles. Stay away from these runout zones until the snowpack has a chance to refreeze.

    (1/30/2024)

    Glide avalanches that entrained wet snow. E at 3,000ft in Tumwater Canyon.

    Photo: Matt Primomo

Avalanche Discussion

Wednesday was a wet one for the East Central zone. Stations throughout the zone measured over an inch of rain in a 12 hour period during the day. In the past week, there have been a couple 'peaks' of instability. One probably occurred on Sunday with the initial warmup and change of the upper snowpack from dry snow to wet snow, and another probably occurred on Wednesday with heavy rain. At this point, water probably has made its way through most of the snowpack, except areas of deeper snowpack at higher elevations. This means that water could be pooled up at prevous crus/facet persistent weak layers on Thursday. 

On Sunday, Monday and Tuesday, many natural and skier-triggered, very large avalanches (D2.5-3) were reported throughout the zone and in neighboring zones. Slides off Big Chiwaukum and in Tumwater Canyon were running to the ground (see photos below). This may be just the tip of the iceberg, as visibility has been limited. Control at Stevens Pass ski area on Tuesday triggered very large (D3) avalanches that ran on the Solstice Crust. On Sunday, an avalanche running on the Solstice Crust and gouging down to the ground at Mission Ridge indicated that these deeper, weak layers are active there. With nasty, wet avalanches running on the ground, it'll be advised to stay off of, and out from under steep slopes until the snowpack has time to refreeze. 

Faceted snow over the Solstice Crust was the persistent weak layer involved in multiple skier-triggered avalanches earlier in January, and activity increased as temperatures warmed towards the end of the month. When it began to rain, reports of very large avalanches running on deeply buried weak layers came in from nearly every zone in our forecast area. The overall weak structure of our snowpack has led to the current prolonged period of instability. With an entrenchment mindset, practice patience and only travel in the mountains if you are confident in your ability to avoid avalanche terrain and runout zones. 

If you get out, let us know what you see by submitting a public observation!

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