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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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A few inches of recent snow and strong winds have built a shallow batch of wind-drifted slabs in exposed terrain. Look for these slabs to become more prominent as you gain elevation or approach the Cascade Crest. Cooler temperatures are decreasing the chance of triggering large wet avalanches but not eliminating this hazard completely. 

Problemi valanghivi

  • Wind Slabs

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

    Recent light accumulations have built a batch of shallow wind slabs in higher terrain. Slabs have formed over a variety of wet snow surfaces or crusts, so reactivity may vary from slope to slope. In general, expect these slabs to be larger and more widespread as you climb into alpine terrain or areas closer to Chinook, White Pass, or Mt Adams that received higher snowfall totals.

    Wind slabs often form on the downwind sides of ridges, below cornices, and underneath rock bands or on the aprons below gully features. Small test slopes and quick snowpack tests can provide valuable data points about the reactivity of these slabs. Scoot around steep wind-loaded features that appear freshly loaded, especially if you notice cracks shooting out from under your feet or machine. 

    (1/6/2025)

    Look for cracking as clues of unstable snow. 

    Photo: Joe Dellaporta

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2

    There is no doubt that we’re trending downwards with this wet avalanche problem, but large activity earlier this week, and a slow drop in freezing levels should have you approaching steep terrain with suspicion and caution.  At this point, this problem will likely be most concerning at lower and middle elevations, which experience a lighter refreeze. Regardless of elevation, pay attention to surface penetration and the extent of the refreeze process as you move around the mountains. If you find yourself in unsupportable, wet snow, keep it dialed back and don’t linger under larger terrain. In areas where you find a thick, supportable melt-freeze crust, triggering larger wet avalanches will be less likely. The best way to deal with this tricky problem is to increase your buffer around steep terrain that remains wet and punchy.

    There are plenty of sloppy, wet snow surfaces that could easily push into wet loose avalanches. Use caution on steep features where wet loose could get moving, especially if they could drain into a terrain trap.  

    (3/28/2025)

    Looking at the crown of a very large wet slab avalanche at Crystal Mountain. N, 6600ft,  WS-N-D3-O

    Photo: Dallas Glass

Avalanche Discussion

The Thursday evening storm was pretty underwhelming. Weather stations recorded anywhere from 2 to 4 inches of new snow. We don’t have much weather data up Highway 410 east of the crest, but the Chinook Pass weather station managed to squeeze out 10 inches. If you travel up 410, west of Bumping Lake, expect more heightened avalanche conditions. 

Forecasting wet slab avalanches is notoriously tricky. Despite the cool-down, we’re still concerned about the lingering threat of wet slabs across the eastern zones. We’re coming out of a warm and active period that brought many large to very large natural wet avalanches as recently as Wednesday, March 25th, around Crystal Mountain in the neighboring west-south zone. You can read more about these avalanches in this observation from March 28th here. While temperatures are cooler, the wet slab problem can be unpredictable and requires a bit extra buffer when moving around bigger terrain that remains wet and sloppy. 

If you get out into the mountains, let us know what you see by submitting a public observation here. 

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