Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
4 · Gross
Waldgrenze
4 · Gross
Unterhalb
4 · Gross
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Kernpunkte

A powerful atmospheric river will impact the Cascades bringing heavy snow that will eventually turn to rain with warming temperatures. Very large natural avalanches are likely and may run long distances into seemingly safe terrain below. Avoid traveling in or underneath steep terrain. 

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    2–3

    1-4ft of snow rests over the Valentine's Day Crust, with more in wind-loaded areas and places closer to the Cascade Crest. Temperatures will likely stay cold enough during the beginning of this storm for over a foot of additional snow to accumulate before precipitation switches over to rain. Warming temperatures during the storm will build strong over weak layering, creating very touchy and dangerous avalanche conditions. Avalanches may break widely, step down to the Valentine's Day Crust, and run long distances into lower elevations. Monday will be a good day to avoid any avalanche terrain and let this storm play through before temperatures cool and avalanche danger decreases. 

    (12/19/2021)

    Large avalanches with wide crowns such as this one are possible on Monday.

    Photo: Matt Primomo

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    2–3

    Avalanche conditions will likely get even spicier when snow switches over to rain as snow levels rise to around 7000ft. Avalanches will quickly switch from dry snow concerns to wet avalanche concerns. As the snow becomes saturated, large wet avalanches will run naturally. Snow that feels wet and heavy and rollerballs are the first indications that wet loose avalanches are possible. These wet avalanches will likely involve the new snow and possibly step down to the Valentine's Day crust, becoming very large wet slabs. Once these large wet avalanches get moving, they can run great distances following ravines and gullies into lower elevations and can be incredibly destructive. It will be essential to avoid traveling underneath these large avalanche paths on Monday. 

    (1/13/2022) Very large (D3) wet loose avalanches like this will be likely on Monday.

    Photo: Katie Warren

Avalanche Discussion

An atmospheric river is just moving into the Cascades, and the brunt of the moisture will impact the mountains on Sunday night into Monday. Heavy snow will switch over to rain at some point on Monday afternoon. While there is uncertainty around how much snow will accumulate before the rain, a widespread natural avalanche cycle is certain. Dry avalanches and wet avalanches will both be present and slick crusts will provide a good bed surface for avalanches to break widely and travel into lower elevations, even in areas with minimal low elevation snow. These are conditions where providing large safety margins between you and avalanche terrain is essential. Areas such as Mission Ridge and Blewett Pass have a limited snowpack, and less snow accumulation is expected in those zones. Therefore, avalanches in these areas may be smaller. However, with weak snow and crusts on the surface, it will be important to dial back terrain choices to lower angle slopes. If you travel in these far east areas and find new snow over 6 inches in depth, avalanches will be possible. Look for signs of instability such as recent avalanches, shooting cracks, or collapsing. These are signs you should avoid steep slopes. 

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