Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Our tropical temperatures may peak on Sunday, creating very dangerous avalanche conditions. We expect large, destructive wet avalanches to be easy to trigger and run naturally. Avoid traveling on steep terrain at mid and upper elevations. Pay attention to the terrain above you, as avalanches may travel through elevation bands via drainages and gullies.

Avalanche problems

  • Wet Slabs

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

    Sunday is on track to be the warmest day yet, with little wind to help keep slopes even slightly cooler. Even northerly aspects will be warm enough for wet avalanches. Wet slab avalanches will become increasingly likely due to poor overnight refreeze on Saturday. We also anticipate daytime temperatures above 50 degrees on Sunday to make avalanches very likely. Meltwater will drain into the snowpack, making it easier to trigger wet slab avalanches on deeply buried weak layers. You may be able to trigger them low on a slope or even from below. Wet slab avalanches could break widely across large terrain features on weak layers 2-3 feet below the surface. Avalanches will be most likely midday through late afternoon.How do we manage this problem? Avoidance is the only reliable strategy. Stay out of harm's way by avoiding travel on and under all large slopes greater than 30 degrees, especially during the heat of the day. Lower elevations may see avalanches run from above, so know what terrain is above you and avoid lingering in and near steep drainages that can channel sliding snow from above. Widespread loose wet avalanches may be smaller and more predictable but could gouge deeply and become large and dangerous as they move down through terrain. 

    (1/29/2024)

    An example of a very large wet slab avalanche (d3) from late January.Mission Ridge Ski Area WS-ASu-D3-R4-O/G

Avalanche Discussion

The Cascades are in a stretch of hot, sunny weather. This is the year's first big, spring-like warming event, with high temperatures in the 50's and freezing levels over 10,000'. Even though it is only March, this is a spring shed event. A close call on Saturday, where snowmobilers triggered an avalanche in Ahutanum (East South) that failed on deeply buried weak layers, is an indication of things to come as we continue to warm the snowpack. Sunday may be the warmest day yet and potentially the most dangerous day in the mountains during this summertime weather. These conditions bring a high level of uncertainty about the extent of avalanches, especially with the weak snowpack structure. Smaller wet avalanches, cornice falls, or snow shedding from cliffs can trigger very large avalanches. Consider that this is the time when 'improbable' avalanches are more likely to occur.

The pattern of persistent slab and now (wet slab) avalanches can be challenging for backcountry decision-making. It takes conservative terrain management and diligent patience. Stepping into steep terrain at mid and upper elevations is simply just a game of chance; you may get away with it, or you could trigger a very large avalanche that is likely to injure or kill you. The structure is especially apparent in the eastern Cascades, where the snowpack is generally more shallow than at the crest. If you're venturing into these eastern zones, be prepared to step back in your typical terrain selection and understanding of the snowpack.

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