Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Cold temperatures and plenty of low density snow to blow around will keep you on your toes at upper elevations and in wind-affected terrain over the next few days.  At lower elevations, take care on very steep slopes where a fast-running sluff could knock you into trees, rocks or other terrain traps. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Travel cautiously along ridgelines, looking for wind-textured snow surfaces, and identifying areas where deeper drifts have formed.  Steer around steep open slopes below ridgelines where you can still trigger a wind slab avalanche.  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 simpler terrain.  

     

    Wind slab avalanche below ridgeline near Cutthroat Pass from a prior season.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–1.5

    With cold temperatures and additional light snow forecast through Christmas Day, you're likely to trigger or see natural loose dry avalanches in very steep and non-wind affected terrain.  Take stock of the terrain where you could trigger a fast running loose dry avalanche or sluff, and avoid slopes where you could be pushed into a terrain trap like trees or over a cliff band.  

    (12/23/2021)

    You may trigger loose dry avalanches like this one seen in the L. Wentachee area Thursday.

    Photo: Nate Hough-Snee

Avalanche Discussion

New snow has incrementally piled up since the Winter Solstice, with storm totals of around 2' in the Hwy 20 corridor.  Several reports from Thursday and Friday found the recent snow unreactive to quick tests and was generally loose and lacking a slab structure.  Earlier this week observers reported finding surface hoar on Delancey Ridge and in the Hairpin Valley in the typical valley to mid-slope locations.  They also noted steeper S-SW slopes had formed a thin sun crust.  It remains to be seen if these layers warrant more attention over the coming days and weeks with incremental loading events.    

A 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 3-5 feet below the surface, especially on slopes near and above 6000 ft.  While avalanches were confirmed on this layer earlier this month, we haven't seen any recent activity and observers continue to log highly variable test results on the crust.    

Merry Christmas/Happy Holidays from the NWAC team and stay warm over the next week! 

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