Avalanche forecast

East Slopes North

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Strong winds and new snow will develop dangerous avalanche conditions at upper elevations. You could easily trigger large avalanches in wind drifted snow. Avoid steep open slopes with stiff wind-drifted snow and seek out lower angle or sheltered terrain instead.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2

    Westerly wind will remain gusty through Friday. Stronger wind and snow overnight drifted slabs near and above treeline, making it easy for you to trigger avalanches. Watch for patterns of drifting and any actively blowing snow to point out the leeward, loaded slopes. Use caution near and below cornices. They've grown large and can fall without warning.The most likely places to trigger wind slabs will be steep slopes below ridges, steep convex rolls, and the base of cliffs. Feel for stiff over soft snow layering and look for signs of cracking or collapsing to identify and avoid areas of unstable wind-drifted snow. Cold temperatures may have created weak snow surfaces. Therefore you could find reactive storm slabs on steep slopes in sheltered areas. You can use small, inconsequential test slopes and quick hand pits to observe how the new snow reacts. Avoid steep terrain if you find the new snow sliding easily or test slopes producing mini avalanches.

    (3/1/2023)

    Cracking in a small wind slab. These shallow slabs were reactive on Wednesday. 

    Photo: Willie Webster

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    In many sheltered areas, you can trigger small avalanches on steep slopes. Loose, incohesive snow could slide below your feet or machine. While these avalanches often are easier to avoid once triggered, they can be dangerous at times. Be especially cautious in very steep terrain near rocks, cliffs, tight gullies, and other terrain traps. If loose avalanches run particularly fast or are forcefully, take care to stay out of them and not be below the moving snow.

    (12/11/2022)

    An example of small loose avalanches.

    Photo: Marshall Baxter

Avalanche Discussion

NWAC observer Willie Webster found shallow reactive wind slabs on Wednesday. The sun was a short-lived visitor, and soft snow and wind-affected surfaces were the primary surface conditions. He also identified weak snow below the Valentine's Crust that was very reactive in snowpack tests, and he experienced some isolated collapses on this layer. He noted the instability seemed isolated to the 4000-5000ft elevation band. This crust can be found up to 7,000ft in the zone and varies with elevation and proximity to the crest. While we have not seen any avalanche activity on this layer, we are closely monitoring this interface as snow buries it deeper. Over the last week, large cornices have failed. With additional wind and snow, these behemoths will only grow larger and potentially more sensitive. They are a hazard on their own but also could trigger an avalanche as they land on steep slopes below. Best to give these hazards wide margins as you travel. 

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