Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Stormy weather will lead to generally increasing avalanche danger throughout Wednesday. You may see small avalanches becoming easier to trigger during periods of heavy precipitation or as the temperatures warm. Don’t let one of these smaller slides carry you into a creek or over a cliff.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    It’s hard to put a label on Wednesday’s new snow avalanche problems. Early in the day, you may only notice unstable snow in wind-loaded areas. However as temperatures warm and snowfall rates increase, you could start to see shallow soft slabs breaking on a variety of steep and convex features even in sheltered locations. This means you will need to adapt to the changing conditions. In the morning be careful around pillow-like drifts below cornices and in rocky terrain. As more snow starts to pile up, you’ll need to consider all open convex rollovers. While we expect avalanches to break at the base of the new snow (1/17 int), you may see slides occurring as deep as the 1/14 crust. Fortunately, in all these cases, the avalanches should remain small even if they run far and fast on the firm bed surface. Don’t let them take you for a ride into a creek or over a cliff.

    (12/20/2022)

    Example:  You could see small natural storm slabs like this as temperatures warm. 

    Photo: Public Observation

  • Loose Wet

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

    Warming temperatures should bring rain to near or just above Pass level during the day. This should result in wet heavy snow that produces rollerballs and small loose wet slides. There’s not a lot of snow over the 1/14 crust at these lower elevations. This will help limit the size of these avalanches. However, don’t underestimate them. Similar to the dryer slabs higher in the terrain, these point release avalanches could run quickly on the underlying crust and carry you places you don’t want to go. If you see new rollerballs or small loose wet slides, expect similar avalanches on nearby slopes.

    (1/14/2023)

    Example: A large rollerball from last week's rain on snow event. 

    Photo: Public Observation

Avalanche Discussion

While not a particularly impressive storm, these types of days are all about consequences. When you look at your route, consider what would happen if a small slide took you for a ride. Creeks, cliffs, and gullies can all turn little avalanches into big deals. 

We’re mainly worried about the snow above the 1/14 crust. You’ll find this depth increases from 2-4 inches to 6-8 inches as you ascend in elevation. During the day Wednesday, you could see another 4 inches fall. If a Puget Sound Convergence zone takes aim at the Pass later during the day, you could see greater totals along with higher precipitation rates. As you travel, use hand pits and small slopes to look at and test these upper snowpack layers.

Over the past few days, small wind slab and loose avalanches have been reported around the zone. Most of the wind slabs occurred in rocky terrain like couloirs and below cliffs. While these same locations could still produce the largest slides Wednesday, we’re expecting a more widespread issue by the end of the day.

Regioni coperte