Bollettino valanghe

East Slopes North

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

Use caution in very steep terrain where you could trigger a fast-moving sluff.  Sunshine and slightly warmer temperatures on Friday will increase the chances of loose wet avalanches on very steep sunny slopes and from releasing below cliff bands.  Persistent slab avalanches remain unlikely but are something you need to evaluate before entering more consequential terrain. 

Problemi valanghivi

  • Loose Dry

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

    Loose avalanches are possible on very steep slopes at mid and upper elevations around the dial on Friday and are more likely near the Cascade crest. 

    You're more likely to trigger a loose dry avalanche on convex roll-overs or slopes 40 degrees or steeper in shadier, cooler terrain.  If temperatures warm a few degrees on Friday as forecast,  small loose wet avalanches, natural or human triggered, will become more likely on very steep sunny slopes.  Loose avalanches can be dangerous if they push you into terrain traps such as trees, rocks, or gullies. When traveling on slopes, be sure no one else is below you.  

    (2/21/2022)

    Loose avalanches on a steep slope in the Stevens Pass zone. 

    Photo: Public obs

  • Persistent Slabs

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

    Persistent slab avalanches have become difficult to trigger. On the off chance that you trigger one, the consequences could be serious. You can still find the weak layer in snowpack tests on shaded slopes near and above treeline. When in doubt, consider steering clear of shallow, rocky, or unsupported steep slopes.

    Indicators of persistent slabs are whumpfing collapses and snowpack tests that pop or drop suddenly. While it's been 2 weeks since the last reported persistent slab avalanche, observers reported these signs of instability more recently. You can dig and find the late-January weak layer about 2 feet below the surface. This layer is a combination of weak sugar-like facets sandwiched between two crusts in many areas. Sometimes you'll find weaker snow above the crust. The weak layers are deepest near and west of the Cascade crest and in wind deposited areas. 

    (2/5/2022)

    A skier triggered avalanche near Maple Pass. Three people were caught, one was carried over 400ft with no injuries. E, 6,600ft

    Photo: NWAC public obs

Avalanche Discussion

After another cold overnight, temperatures will slightly moderate on Friday with generally light winds forecast.  Keep an eye out for any new wind slabs that may have built above treeline on Thursday during periods of moderate northerly winds.  You're unlikely to trigger an older wind slab formed earlier in the week.  A storm last weekend brought about 10-14 inches of snow with westerly winds near Washington Pass with much lower totals for areas further east in the zone.  

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