Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Moderate amounts of new snow plus strong winds are expected Saturday. You are most likely to encounter an avalanche in steep terrain harboring slabs of wind drifted snow. Identify and avoid wind loaded areas to reduce the risk of triggering an avalanche. Warming will likely initiate wet avalanche activity at lower elevations.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Though many of the two day-old storm and wind slab layers are stale and unreactive, new layers will build on top of the old with the next storm. Deeper, more sensitive slabs will likely be found in wind loaded terrain. Anticipate a higher level of danger where you find 6” or more of new snow plus widespread and deep wind transport. 

    Track the depth of new snow as you gain elevation or change aspects. Find test slopes in safe areas to see how the new snow layers react.  Visual clues like blowing snow, cornices, and wind scoured snow surfaces will point towards areas of wind loading. Hand shears can help you track changes in layering and bonding as you travel. When in doubt stick to lower angle, simpler terrain to reduce risk.

    (3/17/2022)

    New  wind swail on Maggie's Ridgeline, Hurricane Ridge. Such features often indicate nearby wind loading

    Photo: Sam Luthy

Avalanche Discussion

Reported avalanche activity from the North Cascades was limited to instability from warming with slow-moving wet avalanches in new snow, pinwheels, etc. No avalanche observations were submitted from the Olympic Range. Given the time of year expect to see some form of wet loose activity most days when there is some combination of new snow and strong sun, rain, greenhousing, or a simple rise in temperature.

NWAC and NPS Professionals confirmed that winter conditions have indeed returned to Hurricane Ridge.  The Ridge picked up 3-4" of snow on Thursday, which sits atop a melt-freeze crust on sun-exposed aspects, but likely not on shaded slopes. Below the 3/17 interface, 7-8" of snow fell Tuesday. Both the snowfall Tuesday and Thursday has been redistributed preferentially onto N-E aspects. The stout early march crust is present on all aspects and may have discontinuous pockets of facets just above it. The lack of continuity makes these facets less concerning, but warrants an examination before heading onto large or unsupported terrain features on northerly slopes. Below the recent snow layers, you might find alternating crusts and snow layers.  Although observers found a slightly reactive layer of graupel down 22", we don't expect avalanches to fail below the early March crust.  In the Maggies area, total snow depth is around 86-118" between 4000-5000 ft.

Cornices and swails have grown in size in the past week. Give freshly formed cornices a wide berth while traveling along ridgelines, they may break back further than you expect. They can also help you identify recently wind-loaded avalanche start zones to the lee of the ridgelines.

2021-22 Forecast Schedule: Avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week when the Hurricane Ridge road is closed, forecast information will be updated daily to include expected conditions and relevant travel advice under the No Rating label.

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