Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

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

A return to winter weather will build new slabs throughout the day on the downwind side of ridges. Some of these pockets could trigger very easily and run quickly. Don’t let them surprise you and carry you over a cliff or down a chute.

Problemi valanghivi

  • Wind Slabs

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

    There may not be much in the way of a real wind slab hazard first thing in the morning. However, as the snow piles up and winds increase, expect slabs to quickly grow. Normally, it would be easy enough to just spot the wind slab pocket and go around, but poor visibility could make this tricky. Fortunately, blowing snow should help you easily anticipate wind-loaded areas. In most places, these new slabs may sit over a crust or weak facets. This could cause them to trigger very easily. Even though they’re small, don’t let them catch you off guard in high consequence terrain. 

    The amount of new snow will be the limiting factor for this hazard. So, expect the largest possible avalanches in areas that recieve more than 6-8” of new snow (the volcanoes).

    (3/4/2023)

    Blowing snow and fresh thin cornices hint at nearby wind slabs. 

    Photo: Andy Harrington

Avalanche Discussion

A solid overnight freeze should help significantly limit the avalanche danger first thing Thursday morning. In facet, many areas may experience “generally safe” conditions to start the day (Low danger). However, as the storm ramps back up in the afternoon, expect conditions to quickly deteriorate and avalanche hazard to increase. 

At the lower elevation, some of this precipitation could fall as rain. Fortunately, the snowpack has been through a lot, and should easily handle the additional water. Even still, you may see a few rollerballs or loose wet slides in very steep terrain. These avalanches should only be an issue if you get pushed into a creek. 

There looks like a brief break between storms during the late morning. If this materializes, you could see the sun pop through the clouds. Since it’s March, that may result in rollerballs and small loose wet avalanches within the new snow. This would be a bigger issue near Mt Rainier and Mt St Helens where more significant snow may accumulate Wednesday night. 

In general, we expect avalanche activity to stay at or above the new/old snow interface. A firm crust formed during the recent springtime weather below 5500ft and at higher elevations on the sunny half of the dial. In more shaded areas, cold dry soft snow continues to linger. Below the surface, the upper snowpack appears well settled and strong. We don’t have any significant layers of concern at this time.

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