Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Stormy weather will increase the avalanche danger at Snoqualmie Pass Thursday as more snow piles up. Steer around all open slopes greater than 35 degrees. Expect larger and more dangerous avalanches as you ascend in elevation and in spots where the wind drifts the snow deeper.

Problemi valanghivi

  • Storm Slabs

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

    Human triggered avalanches occurred around the zone over the last three days. Snoqualmie Pass should see more than a foot of additional snow at mid and upper elevations by Thursday afternoon. Besides the new snow, this storm will also bring oscillating snow levels and strong winds. This is a perfect recipe for storm slab avalanches. Stay off of all open slopes greater than 35 degrees. Expect slides to fail within the new snow particularly during periods of heavy snowfall or warming temperatures. You can use small slopes and hand pits to identify which layer of new snow is currently failing. However, given the dynamic nature of storm events, anticipate that conditions will change throughout the day. Expect larger and more dangerous avalanches at higher elevations and on wind loaded slopes. 

    For several days we’ve mentioned the potential for buried surface hoar and/or facets at Snoqualmie Pass. So far, no avalanches have been reported on this layer, however, human triggered persistent slabs did occur on Wednesday at nearby Stevens Pass. A large amount of uncertainty exists around this potential weak layer. You are most likely to find buried persistent grains in near treeline areas a few inches above the very prominent 12/09 crust. If you see long shooting cracks or feel collapses, seek out lower angled slopes away from any avalanche terrain.

    (12/16/2020) This avalanche occurred in Alpental Valley on Tuesday.

Avalanche Discussion

This storm comes as part of a very active weather pattern that impacted the Snoqualmie zone accumulating 10-20” (25-50cm). This storm will add to that total. Any avalanche actively should remain above the very prominent 12/09 crust. This will make weak layers easy to observe since you can simply dig with your hand to investigate the recent layers and new storm snow. 

At lower elevations, rain and wet heavy snow could create a few small loose wet avalanches isolated to very steep rocky slopes. The snowpack at these elevations has been through a lot over the past few weeks with warm temperatures and other rainstorms. As a result, we don’t anticipate a significant hazard below the rain-snow line. Instead, expect challenging travel with areas of thin coverage, open creeks, and shallowly buried obstacles. 

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.

Regioni coperte