Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

UPDATE: 0730: A Puget Sound Convergence Zone crushed Snoqualmie Pass last night, bring storm totals at middle and upper elevaitons to over 2 feet. Expect dangerous avalanche conditions to develop quickly as you gain elevation. You could see avalanches break within the new snow or down on the old crust on any open slope greater than 35 degrees

Avalanche Problem has been changed from Wind to Storm Slab to reflect the higher-than-anticipated storm totals and the danger rating was raised from Moderate to Considerable. 

Problemi valanghivi

  • Storm Slabs

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

    There's a lot of fresh snow at the Pass! Snowfall rates overnight were impressive, with stations frequently showing 2 and sometimes even 4! inches per hour. This could lead to a variety of inter-storm layers. These weaknesses should be most reactive in the morning hours and during periods of heavier snow showers. We also can't rule out a slide breaking all the way down to the old crust resulting in substantially larger avalanches. 

    This could be a good day to dial it back as you ascend to middle and upper elevations. Any steep open slope should be suspect. While you can use hand pits to gain some information about the new snow, small slopes and uptrack tests may have more limited utility due to the depth of the new snow. Unless your skis, snowmobile, or snowshoes touch the old crust, you may not fully test the new snow. 

    Avalanches could be larger and easier to trigger in wind-drifted areas near ridgelines and exposed features. 

    At lower elevations, the storm total is closer to a foot. With such a shallow snowpack and so many shrubs/trees, we don't expect nearly as much avalanche danger. However, a small loose avalanche could easily push you into a creek, or a very isolated very small wind slab could form in bigger exposed areas. 

    (2/17/2023)

    Example: Handpits can give you some information about the new snow. Look for strong over weak snow, and layers that fail easily. 

    Photo: Andy Harrington

Avalanche Discussion

Winter returned to the Snoqualmie area on Thursday. While only a few inches of snow accumulated at Pass level, 4-6 inches fell at mid-mountain Alpental, with 6-8 inches higher in the terrain. It’s nice to see snow falling out there again!

So far, information about the new snow is scarce. Reports from Alpental pro patrol indicate minimal wind drifting mid-day Thursday. Of course, all this new snow is accumulating on the wet, punchy snowpack from recent rain events. A more stout crust should develop as the new interface (12/6) cools. 

Even with the new snow, this week’s rain decimated the snowpack. Roaring creeks, shallowly buried rocks, open holes, and plenty of trees could make travel tricky, particularly at lower elevations.

Regioni coperte