Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Tue
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Wet slabs may release, and could be destructive as the slow thaw continues. Don't underestimate steep slopes being wetted by rain, even roof avalanches could be dangerous on Monday. Expect challenging travel with a stout crust, breakable crust, and deep mushy wet snow.

Problemas de aludes

  • Wet Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2–2.5

    The snowpack is going through a transition to wet snow, and we could see a variety of dangerous avalanches on Monday. As water makes its way deeper into the snowpack, widely propagating slabs may begin to occur. Buried layers of small facets, surface hoar, and larger facets near the ground could all act as the weak layer for destructive wet slab avalanches. You may be able to trigger wet loose slides that entrain deeper snow and become large as well. In other areas, you might just find challenging travel with a stout crust, breakable crust.

    The current conditions are a bit unusual, and wet slabs are tricky to predict, so give yourself an extra margin of safety with your travels. This means steering well out from underneath large, steep slopes that have been saturated by rain. Look for recent avalanche activity as the number one bullseye of instability information. Wet, mushy, and unsupportable snow are also good indicators that wet avalanches are possible. 

    If roofs begin to release snow, use extra caution around buildings. Roof avalanches can be large enough to bury and kill people.

    (12/25/2022)

    Example slab avalanche involving wet snow at Snoqualmie Pass.

    Photo: WSDOT, SCR Avalanche Crew

Avalanche Discussion

Another round of rain is expected to fall Sunday night into Monday. The lowest elevations have a thickening freezing rain crust, while water is slowly saturating the snowpack higher up. Combined with our previously low density, dry, cold and layered snowpack, this makes for a very challenging and complex situation. Over the weekend, the areas near the crest picked up substantially more precipitation than the Wenatchee mountains. WSDOT reported a number of large natural slides that hit the closed highway in Tumwater Canyon on Sunday. Water amounts near the crest are: 2.2" at Sasse Ridge and 2.7" at Trinity, however these may be much different places at the moment. Sasse likely has a thick freezing rain crust and saturated wet snow. Trinity has 6" of heavy, dense new snow, a freezing rain crust and is later to the party, just now becoming saturated. Many NWAC weather stations haven't registered precipitation well, as they were clogged with sleet. The snowpack has only begun to transition to wet snow near the surface. It'll take time for it to adjust, and in doing so we could see large and surprising avalanches. Keep your wits about you if you do go out into the mountains, it's likely to be a dangerous place on Monday.

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