Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Where you find 1 foot or more of harder, more cohesive snow overlaying softer, sugary snow, you could trigger an avalanche large enough to bury you. You can dig down to look for this snowpack setup, but for a safer and more enjoyable day in the backcountry that doesn't tempt fate, steer around complex terrain and slopes steeper than 30 degrees.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2

    This type of avalanche can break in surprising ways, wider than expected, and from flat terrain, but rollovers and convexities are prime terrain features for initiation. Areas where the setup for this problem exists will be closer to the Cascade Crest. Slabs will be particularly sensitive where the wind has made them deeper and denser on downwind slopes. Wind-loaded slopes are often found just below ridgelines and in cross-loaded gullies. Rippled, uneven snow surfaces and cornice development will point you toward where this suspected terrain is.

    As you move around the terrain, pay attention to the depth and cohesiveness of the new/recent snow. You're looking for the poor snowpack structure laid out in the Bottom Line. Cracking, collapsing (whumpfing), and recent slab avalanches are clear indicators that instability exists, but you might not see any before it's too late, which makes managing this problem tricky. When push comes to shove, you can just default to low-angle terrain free from overhead hazards.

    (2/3/2025)

    A skier triggered persistent slab avalanche near White Pass. This slide released over a 100ft wide and 2-3ft deep. WNW, 5600ft SS-ASu-D2-R2-O

Avalanche Discussion

We are moving further away from the initial heavy loading events that put the persistent slab problem on the forecast. However, we are working with a snowpack that is uniquely weak and abnormal to the PNW. It is still too soon to put total faith in a steep slope's stability when you otherwise might have. NWAC Forecasters in both this zone and the West South zone found signs that the snowpack is still unstable on Friday. Give yourself wider safety margins and put together a conservative route plan for the day while we give the snowpack more time to heal. There is plenty of stellar (pun intended for the snow nerds out there) powder riding and skiing on low angle slopes!

Near the Cascade Crest, you may encounter sluffs of dry loose snow in areas that have not seen direct sunshine. A small avalanche could knock you over and carry you into hazards such as rocks and cliffs. Be mindful of the terrain below you, and be prepared to manage your sluffs.

With all of this soft, dry snow, it won't take much for it to get picked up by even light wind. Don't rule out the possibility of encountering a small wind slab avalanche. Wind-loaded snow could be found at upper elevations on all aspects, but you are more likely to find thicker slabs and cornice development on northerly slopes. Similar signs of cracking and recent slab avalanches will indicate instability.

Submit an observation to help NWAC Forecasters reduce uncertainty. It can be short, simple, and even anonymous. Any information you have will help us write more accurate forecasts.

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