Bollettino valanghe

West Slopes Central

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 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

With a dearth of recent observations, it’s up to you to figure out the stability of new snow layering. You might find avalanche danger greater than depicted depending on where you go in the mountains, especially at upper elevations. Stick to lower-angle terrain with less wind exposure to reduce the likelihood of triggering or being caught in an avalanche. 

Problemi valanghivi

  • Storm Slabs

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

    There’s enough new snow and wind to blow it around, but the reactivity of recently formed slabs is mostly unknown. Are they bonding well? Still reactive? Formed over the old snow surface of weak facets or surface hoar? 

    Look for instability in all terrain using test slopes, hand shears, or anything else you can think of to test the bond of new snow layers. Whumphing, shooting cracks and recent avalanches are all signs you'll probably trigger an avalanche if you head into steeper terrain.

    Dig around in the new snow to look for a stronger over weaker layer. Snowpits and testing might reveal buried surface hoar or weak facets but should be dug in representative terrain. Be prepared to find different layering - and maybe a greater chance of triggering an avalanche - as you gain elevation and change aspects. 

    There is always a better chance of triggering a slab avalanche on steep and convex slopes.

    Photo: NWAC Public Obs

Avalanche Discussion

Continued near and above-freezing temperatures will keep the hazard of wet avalanches in play on Saturday. While any wet avalanches you see should be very small, they can still do some harm in minimally snow-covered, low-elevation terrain full of creek holes, rocks, etc. Don’t linger on or directly under steep slopes where you observe rollers, small wet avalanches, or find wet, unconsolidated snow.

Observations were very limited on Friday with many folks sticking to sheltered terrain close to the trailhead. One group in West North reported no new avalanches, but visibility was poor in that area. No buried surface hoar or facets were identified below the new snow. Overall mid-elevations were quite mild but 6” of snowfall still accumulated at Heather Meadows. Easy-to-trigger wind slabs and signs of wind transport were reported from Snoqualmie Pass.

It would be nice to say that warm temperatures and wet new snow rounded out, melted, and generally beat down the surface hoar and facets. In warmer, mid-elevation areas that appears to be the case. Real alpine terrain usually sees stronger winds and weak snow is often scattered or destroyed at the surface before it snows. The question marks about weak layering are probably in the 5000’ to 6500’ range, especially in areas farther east in the forecast zone that trend a bit colder.

Check out the avalanche forecast for Stevens or Snoqualmie Pass if heading to terrain adjacent to those forecast zones.

Regioni coperte