Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Be sure to steer around unstable pockets of wind-drifted snow near ridgelines, rocky terrain, or convex slopes on Thursday. Potential slabs should be larger and possibly more reactive as you ascend in elevation. Choose travel routes that help minimize your exposure to terrain traps in the event you get knocked off your feet.

Problemas de aludes

  • Wind Slabs

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

    The most likely location for you to trigger an avalanche should be in wind-loaded terrain on Thursday. Keep an eye out near ridgelines, confined chutes, or the base of cliffs where wind-drifted snow likes to accumulate. Visual clues such as newly formed cornices or pillow-like piles that look “fat” can help you identify wind-loaded features you’ll want to avoid. 

    While wind-loaded terrain is the most likely location for triggering a slide, that doesn’t mean you can’t trigger avalanches on steep slopes that are more wind-sheltered. Soft slabs or Dry Loose avalanches could potentially run far and fast on the most recent 1/14 crust. In some instances, they could break in some surprising ways. So use hand pits and test slopes to investigate for potential weak points in the newly fallen snow and keep a lookout for red flag signs of instability such as shooting cracks.

    (1/16/2023)

    A skier triggered Wind Slab from earlier this week that likely ran on the 1/14 MLK crust. This slab was found on the lee side near ridgeline. [NW 6400']

    Photo: Public Observation

Avalanche Discussion

A short-lived storm dropped anywhere from 4-7” around the West South zone on Wednesday and was accompanied by some gusty winds. Precipitation should peter out overnight into Thursday, but the winds may stick around a bit longer, drifting snow into thicker slabs in the usual spots. The newly fallen snow could be most reactive first thing in the morning until we’ve had some time for things to settle out. 

On Wednesday, NWAC forecasters near Crystal Mountain found that the snow at mid to upper elevations near Bullion Basin needed a little more time to settle. The couple of inches that had fallen that morning were poorly bonded to the old surface, failing easily in hand pits and during small column tests. In the meadows and trees, the slab was small and soft which limited the potential hazard. But closer to ridgelines, thicker areas of wind-drifted snow demanded a bit more attention. Small wind pockets and some loose avalanches were triggered on steeper slopes near ridgelines and in some locations, the debris ran well on the 1/14 crust.

The other observation of note was a moderate to poor bond of recent snow to the 1/14 atmospheric river crust. You can likely find this prominent snowpack marker anywhere from a few inches at lower elevations to a foot and a half below the surface at upper elevations. We currently anticipate all avalanche activity to occur above this interface, so be sure to check for interstorm layers or poor bonding before committing to terrain. In recent days, multiple Wind Slab and loose avalanches have been reported above this layer and that pattern could continue as we break into nicer weather in the coming days. Additionally, with the sun possibly making an appearance on Thursday, keep an eye out on the snow surface to see how it might be changing. You could see some loose avalanches or rollerballs as snow sheds from trees and rocks.

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