Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

You could trigger very large avalanches on deeply buried weak layers, especially at middle and upper elevations. Look for simpler, less steep, and more supported terrain while this dangerous problem lingers. In isolated areas of the highest peaks, you may also be able to trigger small avalanches due to fresh drifting from southerly winds at upper elevations

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–2.5

    On many slopes, the snow is still ripe for triggering 2-4ft deep avalanches above a crust. Consider avoiding slopes and staying well out from underneath slopes steeper than 35 degrees. Give larger terrain features wider safety margins than you usually would. At lower elevations, we don't have enough slab over the weak layer for this to be a consistent problem. 

    On Tuesday, at least a couple of recent large avalanches were reported around the Blewett Pass area.  Also on Tuesday, a skier was partially buried in an avalanche on a NW aspect of Jim Hill in the neighboring Stevens Pass zone. These avalanches are failing 2-4ft deep, propagating widely, and being remotely triggered from low-angle terrain below or adjacent to steep slopes. You might not receive signs of instability before the whole slope fails. It could be the 2nd, 3rd, or 8th person on the slope that triggers it. 

    (3/6/2024)

    Large slab avalanche off a steep east facing feature in Owl Creek near Blewett Pass.

    Photo: Tony Stewart

Avalanche Discussion

Friday should be yet another beautiful day in the mountains. A slight uptick in wind may be noticeable on higher peaks and ridgelines. Clouds will be increasing, however, you may still see a few small, loose, wet avalanches. Surface conditions on shaded slopes are mostly still excellent soft, 'recycled powder'. Steeper SE-SW aspects may hold a crust that'll melt down early in the day and might become moist and heavy by the afternoon.

On Thursday, forecasters toured near Blewett Pass. They were able to see the recently triggered avalanche in Owl Creek from a distance, and they found variable test results that showed the persistent slab problem lingering. Tests and layer characteristics indicated that weak layers are slowly gaining strength. Our snowpack is complicated due to the intermittent dry spells in February. Besides the early February Crust, there are also potential layers of surface hoar and faceted grains from the 14th, 18th, and 24th. Widely propagating avalanches could fail on any of these layers. Approach the mountains cautiously and enjoy some low-angle powder until these weak layers gain strength.

This pattern of persistent slab problems can be challenging for backcountry decision-making. It takes conservative terrain management and patience. The structure is especially apparent in the eastern Cascades, where the snowpack is generally more shallow than at the crest. So, if you're venturing into these eastern zones, be prepared to take a step back in your typical terrain selection and understanding of the snowpack.

Regioni coperte