Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

New snow and increasing winds on Saturday will drift cold, dry snow into reactive wind slabs at upper elevations and exposed slopes. These could break a foot or two deep, or could step down to become a very deep avalanche, especially in areas further east in the zone. Steer around freshly wind-loaded areas on steep slopes, limit your exposure to large upper elevation terrain, and be ready to take a step back if finding increasing signs of instability such as shooting cracks or recent slides.  

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Thicker and more reactive wind slabs may build at upper elevations with increasing wind during the afternoon. Keep an eye out for wind-affected snow which appears pillow-like or textured, and feels hollow or stiffer. Wind is forecasted to increase throughout the day, so you may notice more dangerous conditions above treeline in the afternoon. Wind affected snow will avalanche easier than non-wind affected snow, but you could still trigger storm slab avalanches outside of the wind zone within the upper 3ft of snow. We have lingering uncertainties from a buried  suncrust (February 11th) on steep South aspects. Loose dry avalanches could easily run in the new snow as well. 

    Avoid wind loaded pockets on steeper slopes, and use conservative route finding at upper elevations. Look for signs of active wind drifting, and shooting cracks through freshly drifted snow to clue you into areas to avoid.

    (2/19/2021) Cornices and drifts like these along the ridgelines can help you identify wind loaded features.

  • Deep Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–3

    If you find a sweet spot, it is still possible that you could trigger an avalanche on the mid-January persistent weak layer, now buried 5-7 ft deep. 10 days have passed since the last known avalanche ran on this weak layer. With our recent new load and a lack of observations, continue being cautious of this layer while so much uncertainty is present. Stay well away from big, steep, and open slopes near and above treeline. Put a large buffer of terrain between where you travel and large avalanche paths, especially in wind-loaded areas.  

    (2/9/2021) Persistent slab avalanches that may have run naturally on an east aspect at around 4900ft in the Knox Creek drainage above Cle Elum Lake. These are suspected to have run on the mid-January crust later in the storm cycle of Feb 5-9th.

Avalanche Discussion

66 inches of snow has fallen at the Brooks weather station on Steven’s Pass since February 12! Observers report that the whopping storm snow is quickly settling out, and what was once oppressively deep backcountry travel has turned to just normal, enjoyable powder snow. Tree well and deep snow immersion hazards remain a high consequence with all the recent snow. Be sure to stay near your buddies while traveling through the trees and near creeks. Find out more about deep snow safety HERE. 

Observers found one recent storm slab on Friday morning near Skyline, and ski patrollers triggered small windslabs while on control at Stevens Pass Mountain Resort. We received reports of widespread avalanches from the 16th, ranging in size from D1-D2.5. One of these was a very wide storm slab avalanche on the South Face of Mount McCausland (See photo below). WSDOT avalanche workers triggered multiple large and a couple of very large avalanches during control work early Tuesday morning. On Monday, an observer reported natural avalanches on steep southerly aspects below Skyline Lake. 

An atmospheric river looks to slowly enter the region on Sunday, along with rising temperatures, winds, and precipitation turning to rain at low elevations. With warming temperatures, heavy snowfall and strong winds, we can say conditions are expected to become very dangerous on Sunday. If you get out on Saturday, be sure to let us know what you find by making 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.

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