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
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A winter-like storm will impact Snoqualmie Pass Saturday night and Sunday, testing our early-season snowpack. You may find that the highest avalanche hazard is first thing in the morning during periods of heavy precipitation or wind. Try to temper your excitement and ease into winter by choosing simple terrain and letting the snowpack adjust to its new load.

Problemi valanghivi

  • Storm Slabs

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

    The incoming storm has us anticipating Storm Slab development above the rain/snow line on Sunday. These slabs will be thicker and possibly more reactive as you ascend in elevation or in wind-prone areas. Strong winds, fluctuating freezing levels, and multiple pulses of precipitation all will aid in producing density breaks and interstorm layers for you to investigate. You can look for these potential failure points by digging down with your hand or shovel to look for heavy snow over weak snow or poorly bonded layers. When in doubt, avoid slopes over 35 degrees until this storm plays out.

    (11/26/2022)

    Quick hand pits while you travel can give you an indication of how new snow has bonded to old snow surfaces or if it has come in upside down.

    Photo: Andy Harrington

Avalanche Discussion

After a relatively quiet day on Saturday, winter is expected to return on Saturday night and Sunday as the pass is set to receive over a foot of new snow. The new snow will be accompanied by some strong winds, which likely will result in dangerous avalanche conditions developing at mid to upper elevations. 

The new snow will be falling on what is believed to be a relatively strong and well-settled early-season snowpack. The real disparity across the zone and elevation bands is the existing height of snow. Lower elevations may have little to none, particularly east and west of the pass proper, and snow depths begin to increase as you ascend in elevation. On Saturday, NWAC forecasters found up to 2 feet of snow at mid-elevations near Kendall Lakes. 

There have been reports of buried weak (faceted) snow near the 11/22 crust in the neighboring Stevens Pass zone. On Wednesday, 11/23, a public observation indicated that this weak snow may have existed in the Alpental Valley. While NWAC forecasters did not find any major layers of concern on Saturday, don’t trust a single hole in the ground. Take a look at the snowpack for yourself wherever you may be recreating. Shallow early-season snowpacks are notoriously tricky and observations across our zone have been limited to date. 

Despite the incoming snow, early-season conditions are still prevalent at the pass. Many natural obstacles such as open creeks, stumps, rocks, or bushes are currently on or near the surface. Although this storm should be a decent snow producer, it will likely take more to significantly increase avalanche hazard at lower elevations. Many trailhead locations may even see several hours of rain before switching to snow. Regardless of your elevation, once the snow starts to pile up, those natural hazards that were easy to spot on Saturday may be just below the surface on Sunday. Travel with care.

Regioni coperte