Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

It sure feels like Santa left us a bunch of coal in our stocking in the form of freezing rain and sleet at the Pass. However, this layer of ice should help limit avalanche concerns at mid and lower elevations. If you see new rollerballs or experience rain on snow, steer around nearby steep slopes. More dangerous conditions could linger higher in the terrain.

Problemi valanghivi

  • Loose Wet

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

    At mid and lower elevations you could encounter two types of loose wet slides during periods of rain. Piles of sleet (icy pellets) may become wet and produce small avalanches at lower elevations. If you see natural point-release slides, steer around similar terrain. At mid-elevations a layer of ice (freezing rain) should all but eliminate avalanche activity. However, if the crust starts to break down, or if you find areas where freezing rain didn’t reach, watch for new rollerballs to indicate unstable wet surface snow. While most of these avalanches should remain small they could ruin your Christmas if they carry you into a gully of over rocks. 

    Even though we feel loose wet avalanches will be the primary concern Sunday, rain reached high into the mountains. At upper elevations unstable wet snow could linger in many forms. Loose wet, wet slab, glide, and cornice avalanches could all occur. In some cases snow may simply shed from rocky faces. It’s the consequences of these uncertain wet problems that are maintaining dangerous conditions above the protection of the freezing rain crust. Stay off of steep open slopes and limit any time you spend underneath big rocky faces. 

    (4/15/2021) Example: When you find a wet, sticky, and punchy snow surface like this you may trigger loose wet avalanches on similar slopes. New rollerballs are also present on the slope. Photo: Andy Harrington

Avalanche Discussion

No one asked Santa for freezing rain for Christmas, but that’s exactly what we got at Snoqualmie Pass.  Bah  Humbug! However, Alpental Ski Patrol and WSDOT gave the NWAC crew an early Christmas gift with some great observations and photos. They indicated a freezing rain crust formed at mid-mountain elevations and sleet fell at Pass level. As warmer air shoves its way into the zone Saturday night, temperatures should rise above freezing. However, at that point, there likely won’t be much in the way of rain to soften this icy wonderland. 

A brief break in the weather on Christmas morning could give you an opportunity to play with your new toys, but the very slick and firm conditions could warrant sharp points to stay upright. Showers should return in the afternoon, but precipitation amounts don’t appear very impressive. As a result, we don't anticipate it will impact the avalanche danger. 

At upper elevations we believe it rained on Saturday. How did the snowpack handle the water? We don’t know. Since it fell on a cold, dry, and layered snowpack, its easy to imagine natural avalanches occurred. However, the size, type, and what layer they failed on remains unknown.

Regioni coperte