Boletín de aludes

Stevens Pass

Northwest Avalanche Center
Ver en el mapa

Peligro de aludes

Mon
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
Open full map
Desactualizado: este boletín caducó 6 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Look for cracking in wind-drifted snow as a sign to steer around steep slopes below ridgelines where you could trigger an avalanche. There is considerable uncertainty about the cloud forecast for Sunday. If the sun breaks out of the clouds, wet avalanches could also become a problem on steep sunny slopes. 

Problemas de aludes

  • Wind Slabs

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

    While winds were mostly light during the recent storm, we suspect that higher elevation ridgelines still experienced enough drifting to form shallow wind slabs. You can use cornice formations and textured surfaces to identify wind-loaded slopes. Widespread weak surfaces were documented before this storm, and wind slabs that formed on these surfaces could be triggered easily.  A great tool for assessing wind-affected snow is to use small test features to observe how the snow reacts. If you see cracking or small slabs, unstable wind slabs are more likely. While we expect wind slabs to be small, they could still carry high consequences in steep, rocky, or confined terrain. 

    Storm totals were modest, and Stevens Pass only picked up about 5-6".  We expect Sunday to be mostly cloudy, but there is significant variability in the forecasts. This new snow may slide easily if it gets wet and heavy. If you start to see rollerballs or small wet loose avalanches, consider moving to lower angle terrain or shady slopes.

    (12/15/2024)

    A shooting crack in a small wind loaded slope. These small features give great feedback on how larger slopes may react. 

    Photo: Ryan Minton

Avalanche Discussion

Stevens Pass picked up a nice refresh of snow overnight on Friday. While it wasn't much, it certainly improved surface conditions. Observers reported small, dry loose avalanches from steep terrain and rollerballs on sunny slopes east of the pass. Slopes that warmed in the sun will likely have a thin surface crust on Sunday, while shady terrain will still hold soft dry snow. We don't have information from upper elevations, but wind drifting at mid-elevation ridgelines was minimal. 

Observers have reported surface hoar and faceted snow on surfaces as of the 12th. A series of sandwiched crusts exists on most slopes, often with weak snow in and near the crusts. These suspect layers are now buried by 5-6" of snow, while it's not quite enough snow for widespread avalanches, these preserved layers could become problematic with additional loading. It will be useful to use small hand pits to check the new interface. Take note and send us an observation if you see buried surface hoar or if the overlying snow doesn't seem well-bonded. 

At low elevations, you may find thick and breakable crusts on or just under the surface. There are also significant travel hazards due to less-than-ideal snow depths. Open creeks, bare ground, breakable crusts, and frozen chunder in forested areas are all things you might have to contend with to get into the more pleasant conditions above about 5500ft. 

Regiones cubiertas