Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

You could trigger slab avalanches over a foot deep at upper elevations on slopes greater than 35 degrees. Clouds and sun will battle once again with potential for another round of wet loose avalanches. Expect a mild day Saturday before winter weather returns bringing heavy snowfall and rising avalanche danger Sunday.

Problemi valanghivi

  • Wind Slabs

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

    The likelihood and potential size of avalanches will increase as you climb higher in the mountains. Stay alert as you transition into wind-affected terrain and look and feel for sudden changes in snow surface texture and hardness. The best chance to trigger a lingering slab avalanche will be in areas below ridges, cornices, or rock bands, and on large convex/unsupported slopes above 4500ft, especially on north and east aspects. In wind-sheltered areas, the recent storm snow is gaining strength and generally well bonded to variable old snow surfaces. Use visual clues to identify and avoid areas of wind-drifted snow in consequential terrain. Recent avalanches, cracking, or collapsing should direct you to lower angled slopes. 

    (3/26/2021) A recent natural slab avalanche (D1.5) at 5600ft on the northeast aspect of Bearpaw Mountain. The avalanche may have been triggered by sluffing or cornice fall and was 40ft wide and up to 1ft thick.

  • Loose Wet

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

    Freezing levels will hover near 4000ft over the next 24 hours, and snow surfaces may experience a weak overnight freeze. Sunshine may be limited by another day of thick clouds, but it may not take much solar radiation to thaw snow surfaces on E-S-W aspects. Be heads up if the sun comes out for any prolonged period of time. Watch for snow shedding from trees and rocks, wet sticky snow surfaces, or fresh pinwheels and rollerballs as signs you may be able to trigger wet loose avalanches on similar slopes. 

    (3/26/2021) Rollerballs and small wet loose avalanches at lower elevations in the Helena Peak area.

Avalanche Discussion

Expect another calm overcast day Saturday before a storm arrives bringing strong winds and heavy snowfall (12-18in) Sunday. Recent snow from the March 18-24 storms is settling and stabilizing, but could still be reactive to the weight of a rider at upper elevations. Variable snow surfaces exist including breakable crusts and wet punchy snow on solar aspects and at lower elevations. Cold dry powder still lingers on northerly slopes above 4000-4500ft. The last reported slab avalanches in adjacents zones occurred on or before March 25th including a very large natural avalanche in wind-loaded alpine terrain on the north face of North Twin in the West North Zone. There were also a few close calls on Shuksan Arm on Tuesday, including a snowboarder-triggered avalanche that resulted in a partial burial. Sadly, a fatality occurred in the Lake Tahoe area in California last Saturday when a snowmobiler stepped too close to the edge of a cornice and it broke on them. You can read the report HERE. Stay far away from the edge of cornices and the slopes beneath them as they continue to grow larger. Glide cracks are also widening, and despite cooler temperatures, exercise caution by avoiding or limiting your time beneath them.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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