Lawinenlagebericht

West Slopes North

Northwest Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
4 · Gross
Waldgrenze
4 · Gross
Unterhalb
3 · Erheblich
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Kernpunkte

Avalanche danger will slowly elevate on Sunday as snowfall intensity increases in the afternoon. Strong winds will redistribute new and old snow into thick, reactive drifts, possibly in more unusual and lower areas than you’d expect. Deeper avalanches are likely as well, so begin your day by avoiding steep terrain on wind-loaded slopes, and begin scaling back and avoiding steep terrain and the slopes beneath them in wind-deposited areas as snow accumulates.

Lawinenprobleme

  • Wind Slabs

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

    Reactive wind slabs will develop and grow larger and become more dangerous as snow accumulates, especially in the afternoon. Due to the strong winds, they may act differently from your usual deposits- you could find them in unusual areas, and at lower elevations than you might expect. 

    You can identify these slabs by feeling for firmer or hollow snow beneath you. Search for visual clues such as pillowy drifts, cornices, or textured surfaces. Shooting cracks is also a good indicator that the snow is unstable. They are most likely to form around rocky features, on the sides of gullies, or on leeward slopes. If you find any of these identifying characteristics, steer clear of wind-loaded slopes greater than 30 degrees.

    (1/1/2022)

    This terrain is very wind-textured, a visible clue to search for. It also produced a small wind slab avalanche, intentionally triggered on this small, easily manageable slope. These are conditions similar to what you might encounter on Sunday. 

    Photo: NPS Rangers

  • Deep Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2.5–3

    A very large natural avalanche occurred in the Baker backcountry on Friday 12/31. I investigated the avalanche today, and found a weak, sugary layer of surface hoar where the avalanche failed (2 feet down where I dug, 200ft away it was 5 feet deep). The surface hoar layer was present on the snow surface when the Solstice Crust formed, and at about 4800ft and higher more surface hoar is present and less crust is noticeable. The surface hoar is not present everywhere, only where it was not destroyed by the wind. 

    For this reason, there is a lot of uncertainty as to where this deep persistent layer is present, and how reactive it is. The stormy weather over the next several days is likely to awaken this weak layer, and very large, dangerous avalanches are likely to occur. For this reason, steer clear of steep, wind-loaded upper elevation slopes, and avoid traveling beneath large, steep, wind-loaded avalanche paths that start at higher elevations as well.

    (1/1/2022)

    This is a shallower section of crown line (top of avalanche) on the very large,  D3, avalanche which occurred on the Shuksan Arm on 12/31

    Photo: Irene Henninger

Avalanche Discussion

Temperatures are warming as the snow intensifies Sunday afternoon. Snow will get heavier, possibly landing on lighter snow surfaces underneath (if there are any soft spots left as the wind hammers us). These warming temperatures could also contribute to a more unstable snowpack in the upper snow layers, another concern to keep tabs on as the storm develops. 

There are several uncertainties as to how this storm will play out, in addition to the added Deep Persistent Slab avalanche problem. Due to the uncertainties, travel carefully in the backcountry, and stick to smaller lower elevation slopes and non wind-loaded areas to maximize your fun.

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