Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Strong west winds with up to 5" of snow will again form dangerous avalanche conditions at upper elevations. Avoid large slopes 35 degrees and steeper, especially where recent westerly wind forms thick slabs. You may still be able to trigger unsurvivable persistent slab avalanches.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    You can trigger avalanches on wind-loaded, leeward slopes 35 degrees and steeper. Steer around thickly loaded and pillowed features. Avoid convex rollovers and slopes steeper than 35 degrees. Fresh wind slabs will form throughout the day. They'll grow bigger and become easy to trigger as the day goes on. You can expect more dangerous conditions at higher elevations. Due to both fresh wind slabs and the potential for deep slab avalanches, you should avoid large avalanche paths, especially at mid and upper elevations. Below treeline, stick to wind-sheltered slopes and well-supported features. Even in sheltered terrain, you may be able to trigger small loose avalanches on steep shaded slopes. 

    (1/28/2021) An example of wind slab on Tye Peak. Photo: Marc Simonpietri

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–4

    The best way to stay safe is to avoid large avalanche paths and overhead start zones. Avoid traveling below large slopes 35 degrees and steeper. Slopes 5,000ft and higher and on sun-exposed aspects are of most concern. 

    With another rapid load of snow expected through Friday, it's too soon to take Persistent Slab avalanches off our minds. On Sunday and Monday, widespread natural avalanches ran big enough to destroy cars and houses. Some of these ran to the valley floor and involved a weak layer of facets and a crust that was buried in mid-January. While Solar aspects appear to have been especially problematic, persistent slabs have also run on shaded, northerly aspects.

    (2/24/2021) A very large avalanche on Sixty-six Hundred ridge in the Icicle drainage likely ran on the 22nd. NE, 6,200ft, size D3.5. Photo: Matt Primomo

Avalanche Discussion

Expect about 5" of new snow near the Cascade crest by Thursday evening with strong westerly winds. This will fall on a sun crust that formed on steeper sunny slopes on Wednesday. On the 22nd, rain fell on previously dry snow to about 5,000ft. The crust is now buried as deep as 2 feet near the crest. From the 20-23rd a massive storm brought up to 6" of water equivalent. Numerous very large and historic natural avalanches ran on the 22nd:

Dirty Face Mtn- both the SE and E faces produced avalanches to at least D3, running far down the mountain with some very deep crowns.

Round mtn- avalanches on SE aspect as well as a D3 avalanche on SW near 5,000ft on Nason Ridge to the west of Round Mtn.

Tumwater Canyon-  Avalanches ran on NE-SE with numerous loose wet to size D1-2 and a few slab avalanches to D2.5. 

In the Icicle drainage:

Sixty-six Hundred Ridge- An avalanche on NE, 6600ft ran size D3, R4 and took out trees

Big Slide creek- A SE aspect above treeline. Size D3.5-4

Mt Cashmere- Above the Eight-mile trailhead.  7,000ft, SSE. D3.5-4

Regions covered