Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Expect just up to 6" of new snow and wind to maintain avalanche danger at upper elevations. You may be able to trigger avalanches where the wind has formed drifts, especially on shaded northerly aspects above 5,500ft. An older weak layer could result in surprising avalanches in the top 2 feet of the snowpack.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Light snow accumulations and wind will form thin slabs on older wind drifts, formed on March 15th. Use caution on leeward sides of ridges and terrain features. Look and feel in the snow for clues such as stiffer, deeper drifts, or sculpted surfaces. Steer around convex roll-overs and slopes 35 degrees and steeper where you see evidence of drifting. You can trigger older drifted slabs, up to 2 feet deep, on shaded, northerly aspects above 5,500ft where the slabs rest on weak snow (March 8th facets). Quickly dig into the upper layers and look for a soft weak layer, just above a hard cust. If you find this 

    (3/18/2022)

    Cracks shooting through the snow are a warning sign that you could trigger an avalanche. This occurred on a steep slope where the wind drifted slabs on the 15th. Blocks of snow slid on the March 8th facets. 5,920ft, NNW, Jim Hill

    Photo: Josh Hirshberg

Avalanche Discussion

Expect another 4-6" of new snow for Sunday. If you find significantly more snow, you may be in an area of more elevated danger. On Saturday, observers on Jim Hill reported about 3" of new snow and moderate blowing snow near and above treeline. They were able to get small pockets of drifted snow to break underfoot. Up to 5" has accumulated since Thursday. On the 15th nearly a foot of snow accumulated above 5,000ft with rain and wet snow at lower elevations. After an initial cycle of avalanches, the storm snow quickly gained strength. Filtered sun in the second half of the week triggered small wet loose avalanches on sunny slopes. 

We've been tracking a layer of faceted grains just above a crust from early March. Observers in the Chiwaukum range consistently found the March 8th facets above 5,000ft and reported significant wind loading on Saturday. On Friday, forecasters on Jim Hill and in the White Pine drainage confirmed the presence of the 3/8 facets and test results that indicate they could produce slab avalanches. See images and videos below. The layer could produce surprising avalanches where it exists under drifted slabs. You can find the weak layer 1-2 feet below the surface on NW-NE aspects above 5,500ft.  Elsewhere, especially in the West South and West North zones, this layer has produced very large slab avalanches. 

 

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