Bollettino valanghe

East Slopes North

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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In sintesi

The first day of 2022 will feel eerily similar to the last few days of 2021.  You'll have to navigate shallow wind slabs at upper elevations, loose dry avalanches in steep terrain features  and very cold temperatures.  

Problemi valanghivi

  • Wind Slabs

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

    Moderate WNW winds may form fresh wind slabs below ridgelines overnight and Saturday.  You're most likely to trigger a slab avalanche just below lee ridges and other wind-loaded terrain features like at the base of cliffs where spin drifts have accumulated over time. If you encounter red flags like shooting cracks or recent avalanches on similar slopes, step back and choose more sheltered or simpler terrain.  

    (12/31/2021)

    Natural wind slab avalanche in the Hairpin Valley.

    Photo: Adam Butterfield

Avalanche Discussion

Observers noted a natural slab avalanche in the Hairpin Valley on Friday after moderate winds moved snow at upper elevations midweek.  They also observed widespread surface hoar up to near 7000';  a layer worth tracking as the storm cycle picks up later this weekend.  Small loose dry avalanches or sluffs were easy to find in steep terrain.  The East North isn't out of the icebox yet, expect a rinse and repeat with low temps NYE around zero and highs slightly improved into the lower teens at 5000'. 

At the interface that was buried around the solstice, observers reported finding surface hoar as well as a thin sun crust on steeper S-SW slopes.  No recent avalanche activity has been observed down to these layers. The last widespread avalanche cycle occurred on Saturday, Dec 18th (up to size D2.5) in the Washington Pass area.  A crust buried in early December can now be found roughly 4-5 feet below the surface, especially on slopes near and above 6000 ft.  We don't know of any recent avalanche activity on this crust, but observers have noted weaker faceted grains (1mm) above it as recently as the 30th. If you get out, submit an observation and help contribute to the forecast. 

Happy New Year from all of us at NWAC!

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