Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 7 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Buried weak layers 2-4 feet deep in the snowpack continue to be a problem. Wind slabs that formed during last week’s storms added stress to these layers, and pose a hazard in their own right. You’re most likely to encounter both of these problems in steep and rocky upper elevation terrain.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    This zone has been plagued by persistent slab problems all year long. There has been just enough snowfall here to build a hefty slab of snow on top of our early season weak layers, but not enough to really put these layers “to bed”. Since they remain close to the surface, the likelihood of triggering an avalanche on this weak snow is higher. Last week, in the northern portion of this zone, I watched as a group of riders remotely collapsed a large alpine bowl from well below the starting zone. The next day, a large avalanche occurred on a nearby slope, wiping out the majority of the season’s snowfall (photo at right). In the Boulders, a significant wind event one week ago was able to set off several large persistent slab avalanches.

    As the days pass without significant loading and the snowpack gets a chance to take a breather, the places where you might be able to trigger a persistent slab avalanche become fewer and further between. However, last week’s avalanches in the White Clouds and the Boulders, unstable snowpack test scores, and continued reports of collapsing in the snowpack let us know that this problem can’t be written off. Today, you’ll be most likely to encounter this problem in similar terrain as in the photo at right. That is, steep, rocky, and heavily wind-loaded.

  • Wind Slabs

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

    4-8” of snow fell in this zone during the trickle of storms last week. Throughout these storms, moderate to strong winds blew from a variety of directions, creating a patchwork of wind slabs in upper elevation terrain. During the final day of snowfall (Saturday), wind speeds dropped dramatically, leaving a thin blanket of low density snow on top of these slabs.

    Overnight, wind speeds picked up a bit, transporting some of the snow that fell at the end of the storm. These slabs are likely to be a bit touchier than the older generations of slabs, but they will likely be relatively small. Older, stiffer slabs underneath will be less sensitive to your weight, but the resulting slides will be larger (photo at right). Expect to find these slabs in upper elevation terrain, near features that slow the wind down and force it to drop the load that it is carrying.

Avalanche Discussion

Yesterday, Chris did a good job highlighting the variability in snowpack character that exist throughout our advisory zones. I’d recommend clicking this link and scrolling down to read his Forecast Discussion to see what he had to say. 

The weather may change quickly, but the types of problems that we are dealing with in our snowpack don’t. Today will be another beautiful day in the mountains; sunshine and soft snow most everywhere you look. But don’t let the picture perfect weather lull you into thinking that the snowpack is perfect too. Hidden under the new snow that fell last week and into the weekend (sorry good people of the WRV), are weak layers of snow that should be keeping you on your toes. 

Yesterday, an experienced backcountry traveler relayed his experience in an observation that is worth reading. Although his group had hoped to enter more consequential avalanche terrain, they didn’t let their desire distract them from the hazards posed by the snowpack. After some snowpack research (hand pits and snowpack tests) and thoughtful consideration of the season’s snowpack history, they decided to reset their objective to something a bit less ambitious and were rewarded with great skiing in the sun. Remember, you can’t go riding tomorrow if you don’t come home safely tonight.

Regioni coperte