Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A break between storms will decrease hazard a touch on Friday, but triggering a large avalanche of wind-transported snow in exposed terrain remains likely. Look for red flags that new snow is unstable, such as long shooting cracks from your equipment, audible collapsing, and recent natural or triggered slab avalanches. If you see small bits of snow rolling down on a sunny slope, a small wet snow avalanche could soon follow.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Small and large sensitive wind slabs were observed in the zone on Thursday. With another dusting of new snow near the Cascade Crest available for transport coupled with cold temperatures, the persistence of these slabs can extend into Friday. A large triggered slab will be running on a slick crust below. Smaller slabs could be running on mid-storm layers that took shape during the system. Wind speeds were reasonably fast during the storm that initiated this problem, so it is possible you could encounter wind-loaded snow at lower elevations as well.

    Wind slabs typically form just below ridgelines and on exposed convexities and gullies. Rippled snow surfaces, cornices, and sharp drifts will be the most helpful visual clues to look for.  Near the Cascade Crest, you may encounter blowing snow, which is a helpful tool to identify where this problem lies as well. Pay attention to the feel of the snow underneath your equipment; a change to denser, pillowy-looking snow indicates the wind carried snow onto that spot.

    (3/13/2025)

    MRSP reported reactive-touchy wind slabs during morning control work on Thursday (03/13).

    Photo: Mission Ridge Ski Patrol

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    The sun is high in the sky this late into the season, there is new snow on the ground that weather inputs can easily influence, and it will not be very windy. All this equals the possibility of a wet snow avalanche. Luckily, the sun should be filtered through high clouds and it will be cold. This will help withhold the size and likelihood. It's unlikely, but not out of the question, to see a wet loose avalanche at upper elevations on similar aspects too.

    The typical initiation of wet loose avalanches involves rollerballs and pinwheels or chunks of snow falling from cliffs and trees. If you're on a sunny slope and the snow is becoming sticky and moist, find lower angle or shadier slopes. 

    (2/23/2025)

    A small natural wet loose avalanche that hit the road on Blewett Pass near mile post 176 (02/23).

    Photo: WSDOT

Avalanche Discussion

The storm that just rolled through the zone brought a good amount of wind. More importantly, it also brought a much needed winter refresh to the mountains, averaging 8-10" across the zone. Things will be pretty quiet on Friday before another system cruises in Friday night. 

With this lull in the weather, avalanche hazard should be a bit lower than Thursday. But it has been a fairly dynamic few days in the backcountry. Before the storm on Wednesday, an NWAC Forecaster traveling in the Salmon La Sac drainage found fairly reactive and widespread 3-7" slabs sliding on a melt freeze crust formed around 03/05. You can read the full observation here. After the storm on Thursday, Mission Ridge Ski Patrol reported touchy conditions, releasing up to 2 ft deep wind slabs during morning control work. These slabs were also sliding on the same crust. With the lull being short lived, approach the backcountry with continued caution on Friday.

Persistent slabs continue to be an issue in the adjacent zone to the north. While we’ve put this problem to bed in the East Central, it’s worth considering in very northern portions or more far-flung parts of the zone. To reduce your risk, you can default to simpler terrain that is planar and short.

Submit an observation to help NWAC Forecasters reduce uncertainty. It can be short, simple, and even anonymous. 

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