Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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

In sintesi

At upper elevations, freshly deposited wind slabs may be reactive to your weight. Warm temperatures and rain at lower and middle elevations make wet snow avalanches possible on steep slopes. Be alert to changing conditions throughout the day and changing conditions as you travel through the elevation bands. Human-triggered avalanches are possible today.

 

Problemi valanghivi

  • Wind Slabs

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

    If you brave the soggy conditions that exist at lower and middle elevations you'll emerge into a different world at upper elevations. Here, precipitation has been falling entirely as snow. This snowfall has been accompanied by moderate to strong winds blowing out of the W-SW. Weather station data is difficult to interpret during mixed rain/snow events, but it appears that 1-3" of snow have likely fallen at upper elevations here. An additional inch or two will fall during the day today. This combination is creating "great" conditions for wind slab formation. Multiple small wind slab avalanches occurred in the past few days, before this new snow fell. Yesterday, professionals traveling on Titus Ridge decided against skiing a slope due to the presence of recent wind slabs.  Avalanches will be larger and more likely today.

    Be on the lookout for signs that the wind has been at work: drifts, dunes, and rippled snow textures are all good indicators of this. While you are most likely to find fresh slabs in upper elevation terrain they may exist in middle elevation terrain as well, thanks to the strength of the wind. If the snow you are traveling through becomes deeper or denser you've found one of these slabs. Cracking and/or collapsing are indicators that the slab you've found is unstable. Many of the freshly formed slabs will be small, but some may be large enough to produce avalanches that can bury a person. Slabs that are deposited on weak snow surfaces, which are particularly widespread at middle elevations, will break wider than you might expect.

    (2/26/2022) Skiers in Pole Cr triggered these two very small wind slabs on Saturday, 2/26. Once initiated, it appears that they entrained weak, sugary snow that exists in the surface layers of the snowpack.

  • Loose Wet

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

    Over the past 12 hours, precipitation has been falling in the form of rain below about 7,500'. Rain will continue today, with the rain line climbing up to 8,500'. Temperatures have been hovering near or above freezing for 36 hours and will stay that way for the foreseeable future. This combination is producing a wet, slushy snowpack, making both natural and human-triggered wet snow avalanches possible. This type of slide starts at a point and fans out as it travels downslope. They can get large quickly and can be destructive thanks to the density of the water-laden snow. Initially, these slides may only involve the upper snow, but as rain and melt-water penetrate the snowpack they will become larger and gouge deeper into the snowpack. These slides can be dangerous even in small terrain—debris can pile up deeply in terrain traps like creek bottoms and steep road cuts. Monitor the snowpack you are traveling through. If you are finding wet, slushy snow more than a few inches deep, these types of avalanches will be possible.

    Be alert to the terrain you are traveling through and the terrain above you. If you are up high playing in the new snow, remember that you will have to exit through soggy lower elevation terrain to get back to your vehicle at the end of the day. 

Avalanche Discussion

CHANGING WEATHER, CHANGING SNOWPACK, CHANGING MINDSET

In our northern mountains, rain is falling at lower and middle elevations and dense, wet snow is falling above this. In our southern mountains, very little precipitation is falling, but warm air temperatures and significant amounts of ambient solar radiation are causing melting in the snowpack. We are coming out of a period of LOW danger that has stretched on for over a month. Today is different. Many of us (myself included!) have been traveling through the mountains with an "open season" mindset, which has been a real treat. But conditions are changing and the way we move through the mountains needs to change as well. Take some time today to think about how you are traveling in the mountains and the hazards you are exposing yourself to. Pay attention to terrain traps like creek beds, road cuts, and gullies. In these areas, debris from even small avalanches can pile up deeply. As you move up through the elevation bands, prepare to encounter changing avalanche problems. Down low you'll be dealing with wet snow problems, up high you'll be dealing with wind slab problems, and in between, you might be dealing with odd combinations of the two. Create some broader safety margins for yourself today to help address some of this uncertainty. And don't forget to pack your rain jacket.

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