Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Tuesday will be a very dangerous day in the mountains. Strong to extreme winds, heavy snowfall, and various weak layers in snowpack are a recipe for large avalanches. Avalanches could break widely and run naturally from overhead. So avoid traveling on or under steep slopes until this storm plays out.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Tuesday won't be a day to venture into avalanche terrain. Natural and human-triggered storm slab avalanches will be widespread. Avalanches could measure 2-4 feet deep and propagate widely across terrain features. Avoid traveling on or under slopes greater than 30 degrees, particularly at middle and upper elevations where avalanches will likely be much larger. At lower elevations with a thinner snowpack, avalanches might be smaller, but they would carry high consequences if you are dragged through terrain still riddled with rocks, stumps, creeks, and other terrain traps. Strong to extreme winds will also drift snow into thicker slabs, where you could trigger a stiff wind slab avalanche. With these high wind speeds, finding sheltered slopes that lack significant wind drifting may be challenging. If you venture out into the blizzard-like conditions for winter recreation, be sure to find sheltered, low-angle slopes not exposed to overhead hazards from steep slopes above. It will be a great day to observe red flag signs of instability, like collapses and shooting cracks, from low-angle terrain.

    (1/7/2024)

    A skier triggered and took a short ride in this avalanche that failed on buried surface hoar in the Teanaway Drainage on Sunday. 

    Photo: Rob Pollard

Avalanche Discussion

Expect blizzard-like conditions in the mountains on Tuesday with heavy precipitation, warming temperatures, and winds up to 65mph. Avalanche danger will increase rapidly on Tuesday night, and we expect natural activity to continue during the day. This storm will overload the various weak layers in the mid and upper snowpack, responsible for multiple human-triggered and natural avalanches in adjacent East Central and West South zones over the past few days. A similar snowpack structure exists in East South, and we anticipate significant avalanche activity on these weak layers. Until this storm passes through and we can reassess the state of the snowpack, travel in avalanche terrain is not recommended. Lower elevations hold less snow and, in many places, likely do not have the threshold for large avalanches. However, we still expect smaller avalanches at lower elevations, and these could carry serious consequences with additional terrain traps still protruding from the thin snow cover.The upper snowpack has several potential and confirmed weak layers and crusts. Surface hoar buried on 1/2 is the suspected culprit in two human-triggered avalanches in East Central. This 1/2 interface, or a crust formed on 12/30, might be the weak layer in an avalanche at Crystal Mountain. The Solstice crust is currently buried around 2-3ft deep and is associated with weak, faceted snow above and below the crust. This layer produced large slab avalanches during control work at Mission Ridge on December 30th, and could be the weak layer responsible for the avalanche at Blewett Pass. We can't rule out avalanches in the new storm snow stepping down to these deeper weak layers and producing very large avalanches that propagate widely. Extra caution and wide margins are warranted while this storm plays through our mountains. Early season conditions still exist across much of the zone. Look for hidden hazards such as downed trees, stumps, creeks, and rocks. These could now be buried just below the new snow!

If you get out let us know what you see by submitting a public observation!

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