Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

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

Expect dangerous avalanche conditions as the latest storm adds to the deep snow from the past week. Avalanches will be easy to trigger, they could be very large, and they may run naturally from higher elevations. Avoid being on or under large, steep slopes where avalanches can start or run at middle and upper elevations.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    Avalanches could break near the surface, at a number of interfaces in the upper snowpack, or even deeper. You're most likely to trigger avalanches in the recent layers of snow near the surface, or where the wind has formed deeper, stiff slabs. Avalanches in wind-drifted slabs could be dangerously large and could involve much deeper weak layers. Even smaller slopes and features at lower elevations could be easy to trigger. If enough sun gets through the clouds, avalanches could become easy to trigger in southern aspects.

    Take time to test the new snow on inconsequential slopes before traveling in terrain steeper than 30 degrees. There's so much new snow that you may need to dig with your shovel to find recent storm interfaces. Choose smaller, well-supported slopes and stay away from complex avalanche terrain. Stay off of and well out-from-under steep start zones in wind-loaded terrain, leeward sides of ridges, and all at upper elevations. Slides that do break to these deeper layers could be over 5ft deep, break widely, and could run long distances downhill. 

     

    Example storm slab from last month.

    Photo: WSDOT SCR

  • Persistent Slabs

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

    Stay off of and far away from steep avalanche paths above 6,000ft. Avoid traveling in areas with complex, overlapping avalanche paths. Avalanches may propagate widely across terrain features, and run full path to lower elevations. These avalanches can be very dangerous and difficult to predict. The best way to manage them is to avoid avalanche terrain where the weak structure exists.

    At and above 6,000ft, avalanches could break weak layers, including facets above the early February crust, 4-6 feet below the surface. These may be most likely in the eastern portion of the zone, where the underlying structure is weaker. Avalanche workers triggered some slides on this layer on shaded aspects on Tuesday, and skiers have reported whumphing collapses on it in adjacent zones in the past couple of days. The heavy snow and wind loading from the last week are stressing the weak structure. Targeted snowpack tests (compression test, deep tap, propagation saw test) can help you identify the problematic layers. 

     

    (2/26/2024)

    Example large avalanche that ran on the early February Crust from the West South zone.

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

An impressive storm will begin to wind down on Thursday after delivering 2-3 feet of snow. As of Wednesday evening, the Stevens Pass area has received 4" of water equivalent, and the snowpack has gained 3-4 feet since the 24th.

On Tuesday night and Wednesday, avalanche workers triggered large and very large (up to D3) avalanches in the recent snow. On Tuesday, multiple observers reported sudden planar test results with compression tests on small faceted grains above the early February Crust. These came in from Grace Lakes and Lanham Lake areas on northerly aspects. Two significant (D2+) natural avalanches were observed from the Camp Chutes off the south side of Rock Mountain on Tuesday. The timing of these is unknown but estimated between the 26-27th. The slides ran down to the bottom of the track (gullies) at least. A wide slab avalanche occurred on a SE aspect at 5,600ft in Highlands Bowl on Monday, this was triggered by a smaller sluff. That same day control work at SPMR triggered a few avalanches that broke down to the early February Crust.

Riding conditions have been excellent, but with the incoming warming storm it'll be time to let the mountains ride out the storm. The very dangerous conditions are expected to last through the evening and natural avalanches may continue well into the overnight period on Wednesday. 

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