Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Warm temperatures are beginning to take their toll on the upper elevation snowpack. Wet loose avalanches may be triggered on very steep, sunny slopes after a few hours of direct sun. Time your travels to stay off of steep slopes if they become wet and punchy, and minimize your time underneath cornices. 

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Snow surfaces are undergoing rapid change each day. Strong sun and warm temperatures are melting it into wet/sticky snow after just a few hours of direct sun. Expect wet snow on southerly aspects and moist, sticky snow over drier snow east and west aspects. As the day warms you may increasingly find areas where you could trigger rollerballs and small loose wet avalanches. Some of these could be large if the terrain feature is just right, such as large features at higher elevations. Cornices may fail sporadically with warm temperatures. Cornices could also trigger larger avalanches on some slopes. 

    If you observe wet, gloppy snow and rollerballs, expect you could initiate wet loose avalanches on very steep slopes. Keep in mind overhead hazards or other areas where getting caught in even a small, wet avalanche may hold increased consequences. Use caution, and avoid exposing more than one person to avalanche terrain at a time or move to a different aspect or less steep slopes.

    (2/10/2022)

    Wet loose avalanches on the lower flanks of Lichtenberg Mountain. The smaller ones on the right likely occurred on 2/9 or 10, while the larger one may have occurred on a previous day.

    Photo: Matt Primomo

Avalanche Discussion

We're in the middle of a warming trend that should continue through the weekend. The very warm temperatures and stronger sun of mid-February are beginning to take it's toll on the previously dry 1-2ft of storm snow from earlier in the month. Wet loose avalanches were reported at both Stevens and Snoqualmie Passes on Thursday and Friday, and these may continue to occur through the weekend, though may need a trigger to get going. 

A weak layer associated with the long dry spell in January is rounding and strengthening. Faceted grains sit above a stout crust from late January 1-2ft below the surface. The weak layer was problematic in the zone on NW-NE aspects between 4,000ft and 4,700ft. Most observations point to inconsistent snowpack test results, although sometimes observers are still getting test results that indicate avalanches are possible on this layer. One observation from an east aspect at 6,000ft shows sudden collapse results in one test, and no results in another. Previous observers targeting it on northerly aspects have reported overall strengthening and decreasing likelihood of triggering avalanches. There is uncertainty how very warm temperatures may influence chances for these persistent slabs through the weekend, but it's possible that large cornice falls or large wet loose avalanches could trigger larger, more surprising avalanches. Backcountry travelers were surprised when they triggered large avalanches on similar layers in the West North zone, and East North zone last weekend. 

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