Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Fresh and shallow wind slabs will likely develop on open lee slopes at upper elevations and below ridgelines as an incoming storm impacts the area late Saturday night and Sunday.  Take the time to evaluate the snowpack if you're headed to eastern parts of the zone that may have a shallower and weaker snow structure. 

Problemi valanghivi

  • Wind Slabs

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

    There's just enough new snow along with moderate to strong ridgeline winds late Saturday night through Sunday that fresh wind slabs should develop on lee slopes above treeline.  Shooting cracks or hollow-sounding snow are signs you could trigger an avalanche on similar slopes. Steer around obvious wind features like freshly drifted snow and wind pillows.  Avoid steep slopes below cliff bands where spin drifts may form localized wind slabs that could release naturally or with your help.  If you find that similar conditions extend further down in elevation,  seek out lower angle and wind-sheltered terrain. 

    (2/6/2021) A skier intentionally triggered a small wind slab avalanche on a SW aspect at 74000ft near Washington Pass.

Avalanche Discussion

The start of March marked a change from our cold and snowy February with milder temperatures, periods of sunshine and freezing levels rising as high 7000'.  Cooler temperatures arrived late Friday night, helping to reduce the threat of cornice fall that had peaked earlier in the week.  Observers in the Varden Creek drainage on Saturday found 2-3" of new snow along with stubborn shallow wind slabs on isolated features above treeline.  At 6600', the mid-January crust could be found down around 4' but was unreactive in snowpack tests.  The crust disappears in this area above 7000'.  The most recent February avalanche cycles in this zone likely released down to the 2/21 interface.  Avalanche debris from the latter half of February is still visible in many paths. 

Persistent slab avalanches are unlikely in this zone but not impossible. You may encounter persistent weak layers in areas with a snowpack of five feet or less such as the eastern mountains around the tributaries of the Chewuch and Twisp River drainages. Check out this observation from Wolf Creek last week. Other forecast zones have been plagued with very large and destructive avalanches in the past 2 weeks. Be sure to check out the forecast for the East Central zone if you are traveling to the southern or eastern edge of this zone for more details on the problematic mid-January crust/facet weak layer. 

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