Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

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

You can trigger avalanches in the recent snow on slopes steeper than 35 degrees where you find weak surface snow or recent wind drifting.  Extremely cold temperatures will keep the snow light and dry on most slopes. Be prepared for difficult travel through deep snow and the coldest temperatures of the season.

Problemi valanghivi

  • Loose Dry

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

    You can trigger loose avalanches in the surface snow on slopes 40 degrees and steeper. While these avalanches are typically small and can be easy to manage with experience, they can be dangerous especially around terrain traps. Watch out for traveling in steep terrain with features like gullies, cliffs, and trees, where any avalanche could have serious consequences. Make sure to stop and regroup out from under slopes of concern.

    (12/26/2021)

    A skier triggered a loose dry avalanche (D1) on a steep (40deg) slope. Dirty Face Mtn, WSW, 3500ft.

    Photo: Matt Primomo

  • Wind Slabs

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

    Watch for recent wind slabs on leeward sides of high ridges and at unique locations from lower, valley winds. Steer around areas of stiffer, drifted snow, deeper pillows, and wind features. Use caution on wind-loaded slopes steeper than 35 degrees. To avoid these avalanches stick to windward or lower angled slopes or wind-sheltered terrain.

    Winds on Monday drifted snow primarily from the west and were channeled by terrain. Wind slab distribution may be unique and less predictable than with typical wind events. Winds were more pronounced at low elevations near the Cascade Crest or at upper elevations further east of the crest.  The low-density snow could be easily transported by lighter-than-average wind. 

     

    (12/27/2021)

    A small skier triggered wind slab avalanche below a steep convexity. 5,000ft, NW, Big Chief Mtn.

    Photo: Joe Dellaporta

Avalanche Discussion

On Monday, an observer on Big Chief Mountain triggered a small wind slab avalanche in near treeline on a northwest aspect. Saturday was an active day for avalanches. Observers on Arrowhead Mountain triggered a number of small storm slab avalanches (about 1 foot deep) on a west aspect near treeline, the biggest of which broke about 40 feet wide. More recently, observers have reported natural avalanches that likely ran between the 25-26th.  One notable avalanche (D3) broke widely across alpine terrain on a NE aspect of Mt Mastiff. Observers reported another avalanche, at least D2, on an unsupported west aspect near treeline in Henry Creek. We suspect this slope may have also avalanched on the 18th. A number of crusts may be found in the mid and lower snowpack from early to late December. The Solstice crust is thin and can be found about 2-3 feet below the surface. It's worth monitoring this crust with snowpack tests, especially if you are venturing to upper elevations or traveling on the eastern end of the zone.

Since the Solstice, storms totaled over 3 feet at the top of Stevens Pass. While the snow has stopped,  temperatures will continue to drop to rarely seen frigid lows. Be proactive around frostbite and cold weather injuries. The snow is deep, and observers have reported difficult travel conditions and potential for snow immersion hazard. Stay away from tree wells and keep your partners within sight and voice contact. When in town, be aware of the potential for roof avalanches. A roof avalanche in January, 2020 resulted in a fatality at a residence near Blewett Pass. 

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