Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

You can trigger avalanches on steep slopes near and above treeline where the wind drifts snow. Expect gusty easterly winds and snow to form drifts Wednesday afternoon.  Clear skies Wednesday morning will maintain a chance for small wet avalanches on sun-exposed slopes.

Problemi valanghivi

  • Wind Slabs

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

    Search for signs of wind loading by feeling for heavier, thicker snow beneath you. Look for clues such as textured or featured snow surfaces and actively blowing snow. Obvious signs such as cracking, indicate you could trigger an avalanche. If you see this, steer around leeward and cross-loaded slopes steeper than 35 degrees. You may encounter wind-drifted slabs on a variety of aspects at upper elevations. 

    We expect the chance of avalanches to increase Wednesday afternoon as snowfall develops along with strong and gusty easterly winds. This could form freshly drifted slabs, especially in locations where the terrain funnels east winds. Older slabs formed on Monday night and Tuesday with westerly winds. While it's becoming harder to trigger these older drifted slabs, avalanches are still possible.

    (4/18/2022) Moderate winds were actively loading old and new snow midday Monday. This tiny wind lip was about 8" deep, and little chunks were cracking and running from the small feature. They were not concerning here, but applied to higher elevations and with more snow and wind they could break larger. Photo: Irene Henninger

Avalanche Discussion

You may be able to trigger small wet avalanches on sunny slopes if the sun shines long enough to melt the surface snow. Keep an eye on how much the surface melts and use small test slopes to check if it could slide easily.  If so, stick to slopes less than 35 degrees or move to a more shaded aspect.

On Tuesday, most surfaces got moist near and below treeline and should freeze solid overnight. Skies should be clear or be covered with just thin clouds into at least mid-morning. The timing and extent of building cloud cover are uncertain. Monitor the cloud cover and strength of the sun. Similarly, there's uncertainty about how much snow will fall in the afternoon.  Weather forecast models have consistently under-forecasted snow amounts over the past 2 weeks, especially when dealing with east flow events like we expect for Wednesday. If you find more than 6" of new snow, the avalanche danger may be higher than anticipated.

A round of small avalanches (size D1) occurred on Tuesday in the 6-10" of new snow that fell overnight with enough west wind to drift slabs. Observers reported that avalanches were easy to trigger and some ran naturally where the sun warmed snow surfaces sufficiently. Wet Loose avalanches occurred naturally on all aspects, especially at mid and lower elevations. Observers triggered small slab avalanches, mostly on leeward slopes, where the wind drifted thicker slabs. 

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