East Slopes South

Triggering even a small avalanche within new snow at upper elevations may result in a large and deadly avalanche that breaks down to weaker, deeper snow layers.  Play it conservative and avoid all avalanche terrain at upper elevations.  Limit your overhead exposure to large avalanche paths at lower elevations. 

Preliminary avalanche incident information Monday February 8th, 2021: Two snow bike riders were caught and buried by a very large avalanche in the mountains west of Salmon la Sac Sno-Park along Cle Elum Lake. One snow biker was partially buried and was able to dig himself out. The other rider was fully buried and killed by the avalanche. The avalanche occurred on a north aspect at 4400 ft in the Knox Creek drainage. This terrain lies in NWAC’s East Central forecast zone. Avalanche classification: HS-AV-R3-D3-O.  See the short video in the media gallery below.

All of us at NWAC want to extend our condolences to family, friends and the local community following this tragic event.  

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The recent storm cycle has brought more wind than snow to the East South zone. Strong to extreme westerly ridgeline winds finally backed off early Monday morning.  Several inches of snow has accumulated above 6000' since Friday with lighter new snow accumulations at lower elevations.  This recent snow has likely become weak over the last few days with intense swings in the day and nighttime temperatures. Snow arriving Thursday will fall on these weak layers making small wind and storm slabs possible. While these slabs may not be extraordinary in their own right, they may be the trigger necessary to release very large deep persistent weak layers that still linger in the area.

Small storm slabs and wind slabs will be likely within the new snow Thursday.  However, we are more concerned about deeper persistent weak layers in the East South zone.  With large and potentially deadly persistent slab avalanches occurring in neighboring zones (East Central and West South), continue to limit your exposure to large avalanche paths until we know more.  Triggering a smaller avalanche or cornice fall could result in an avalanche breaking down to older weaker snow layers.  Persistent slabs can break widely around terrain features. Don't try to manage this problem.  Give yourself a healthy buffer and stick to lower angled terrain at mid and lower elevations that are not exposed to large avalanche paths. 

If you're out in East South, help improve this bulletin by submitting an observation. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.