Bollettino valanghe

West Slopes North

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

If the sun shines intensely on steep slopes, you might see surfaces getting wet, resulting in rollerballs or wet avalanches. Avoid traveling on or under those steep slopes that are wet and you see snow rolling or sliding down them. Increasing wind will redistribute low-density dry snow at higher elevations, so steer around steep, wind drifted slopes.

Problemi valanghivi

  • Loose Wet

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

    Snow may have initially been affected by the sun on Saturday, but Sunday will be warmer and sunnier. More wet loose avalanche activity could result. We expect a crust to form Saturday night on any previously wet snow surfaces. A thin crust above the new snow layer on sunny aspects could break down and get wet, with resulting avalanches in the wet snow. If you notice wet, sticky snow or already see rollerballs or slides, avoid similar steep slopes and terrain beneath them. 

    Don't linger directly under cornices, snowy cliffs, or glide cracks lurking in the terrain above you. The likelihood of seeing additional wet avalanche activity or cornice falls since our large period of rain and warm temperatures is low but not completely out of the question. 

    (3/21/2021)

    Wet loose avalanches often initiate where snow sheds off rocks and trees onto the slope below. In this photo there are both small rollerballs and wet loose avalanches in this image, like what you may see on Sunday. 

    Photo: Zack McGill - Cascade Mtn Ascents

  • Wind Slabs

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

    Increasing winds will develop new wind slabs on Sunday. New snow above our most recent atmospheric river crust varies from a few inches to around a foot, depending on elevation and location in the forecast zone. As you gain elevation, you'll find a thicker snow layer and deeper drifts. These drifts, even if small, may sit over a crust that they could slide easily on. 

    Search for actively blowing snow and rippled or smooth, pillowlike surfaces. If you find new drifts and the snow layer is nearing 6 inches or more over the crust, then steer around steep slopes. Since most new wind slabs will probably be shallower, you can do simple tests to help identify how easily these new slabs run. Although we don't expect this to be the case, non-wind-affected layers may still slide over the crust. 

    Example photo: You could trigger small or large wind slab avalanches on steep slopes on Sunday. 

Avalanche Discussion

There was a very large slab avalanche by Hourglass in the Baker backcountry, which likely occurred Friday night (media gallery). This was probably a residual wet avalanche from our lingering warm temperatures and rain. There were no reports of any human-triggered avalanches in the Baker backcountry from Saturday as of publishing time. 

There are very few recent observations, although a new snow layer finally coats the most recent wet layer, which is slowly becoming a crust. Friday night, we received about 2-3" of snow at mid and upper elevations.  This is on top of about 4” of moist new snow reported in the Baker backcountry at 5000'. This snow sits over that old wet/crust layer. Different locations in the zone could have more or less snow over the crust. On Friday, the new layer was observed to have a poor bond to the old snow surface, but this wasn't reported on Saturday. We expect the best freeze since the warming event on Saturday night, so the old crust will freeze more for Sunday. 

Submit an observation to the website or the Avy App to help NWAC Forecasters reduce uncertainty. It can be short, simple, and even anonymous. 

Regioni coperte