Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Welcome back winter, and welcome back to our readers! The snow will continue at Snoqualmie Pass on Friday, slowly building the snowpack and the avalanche hazard. Be prepared for early season conditions and difficult travel if you head into the mountains. Not a lot is known about the higher elevations, but there could be unstable pockets of snow to avoid.

Problemi valanghivi

  • Wind Slabs

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

    The season is young and observations have been limited, particularly at upper elevations. That said, you could find pockets of unstable snow in the form of small Wind Slabs at upper elevations. Keep an eye out for Wind Slabs on the leeward side of ridgelines or in areas where wind-blown snow likes to accumulate, such as at the base of cliffs or convex features. Visual clues such as textured snow surfaces or wind-stripped slopes are hints that Wind Slabs could exist nearby. If you find pockets of unstable snow, avoid similar terrain features steeper than 35 degrees.

    (11/25/2020) Wind can often drift snow to the base of cliffs creating sensitive pockets. At the start of last season, this slab was remotely triggered from below, wrapped around terrain features, and knocked a skier off his feet. Photo: Charlotte Guard

Avalanche Discussion

As of Thursday evening, Snoqualmie Pass has received about a foot of snow at road level and more snow is on the way. This snow will hopefully be the start of rebuilding our early season snowpack that was severely diminished by recent atmospheric river rain events. In many areas of the zone, the new snow has fallen on bare ground or minimal pre-existing snow. We do not have any direct observations of this snowpack structure, but it likely contains a strong block of snow at its base (Late November Crust), with softer snow above. You will need to take a look at any snow above the Late November Crust for poor bonding before committing to terrain. On Thursday, we received a report of a small slab being triggered by a skier while ascending on their skins. It was likely a Wind Slab much like we described in the problem description and is a good indication of instability.

Regardless of elevation, a relatively shallow snowpack exists throughout the zone, even as the snow continues to pile up. This means that open creeks, stumps, rocks, and other natural hazards will exist if you decide to travel in the mountains on Friday. You may be excited to finally get out and enjoy the snow after what some would consider a lackluster fall season. Try to temper your expectations and take it slow, realizing that we have a lot of winter still ahead of us, and better conditions will exist.

Regioni coperte