Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

As the sun shines expect wet loose avalanches to occur on steep sunny slopes. Monitor the snow surface and when it begins getting moist and rollerballs start coming down, retreat to shady aspects. Start with small test slopes and thoroughly investigate the bonding in the new snow layers before exposing yourself to steep upper elevation slopes on Tuesday where slab avalanches are possible.

Problemi valanghivi

  • Loose Wet

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

    Wet loose avalanches will slide naturally as sunny slopes warm on Tuesday. Keep an eye out for rollerballs or pinwheels rolling down steep slopes, especially in areas with rock bands. As the snow moistens, retreat to shady aspects or lower angle terrain. Avoid traveling under steep terrain with wet slopes above you.

    Human triggered wet loose avalanches are likely in steep terrain. Stay aware of your sluffs which may entrain more snow and surprise you from behind as you travel downslope. 

    An example of a wet loose avalanche like you might see on Tuesday. They could also be larger. Photo: Zach McGill

  • Storm Slabs

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

    Several natural and human triggered slab avalanches occurred on Monday in neighboring zones. Conditions are very similar in the West Central zone. Most avalanches failed beneath the new snow layer- 6-12" deep. Snow was most reactive in steep wind loaded areas, although the wind loading was subtle and slabs remained very soft. Many avalanches appeared more like storm slabs, just requiring slopes in the upper 30 degrees or steeper to slide. 

    Tuesday slab avalanches will remain possible to trigger on steep slopes, especially where wind loaded. You may find them more reactive on shady or leeward slopes. Use small test slopes to determine how readily the recent snow layers slide before exposing yourself to larger slopes. Make sure to enter steep slopes from the top where snow would break below you, rather than travelling in from midway on a slope where snow could slide down from above you. Until thoroughly tested, avoid steep slopes at higher elevations.

    This storm slab was triggered by a skier in Steven's Pass on Monday. Conditions are similar in the West Central zone. The snow was touchy, and sensitivity is expected to have decreased a little on Tuesday.

Avalanche Discussion

At least two feet of snow fell in the West Central zone from 3/18 - 3/22. Our avalanche problems are limited to surface layers, but thise is a substantial amount of new snow. Be sure to investigate these recent layers before committing to steep slopes, as we have seen several slab avalanches running in these layers, and now wet loose avalanches are a concern as well. 

Cornices are continuing to increase in size and weight. They could drop onto slopes below acting as huge triggers. Stand back from cornices along ridgelines and minimize overhead exposure to these features. Several large glide cracks and a few glide avalanches were observed recently as well. Cooling temperatures should limit glide activity for now, but these avalanches are difficult to predict. If you notice crevasse-like cracks in the snowpack, avoid slopes beneath those features.

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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