Lawinenlagebericht

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Human-triggered avalanches are likely today, particularly on slopes where the wind has been drifting snow and adding weight to weak layers buried in the snowpack. Avalanches failing on weak snow buried near the ground will be very large and likely unsurvivable. Avalanches may be triggered remotely—from flatter terrain below, above, and to the sides of steep slopes. 

Read more about what CONSIDERABLE danger means in today's Forecast Discussion.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–3

    We have a layer of very weak snow (facets and crusts) buried in our snowpack. In this zone, it sits beneath a 3-4+' thick slab of dense snow that was built in the past 2 weeks. This weak layer has produced numerous large and very large avalanches already this season, including this slide on Galena Peak that was observed in a period of clear weather on Christmas Eve. Yesterday, in the Baker Creek drainage, I observed several large natural avalanches that had failed within the past day (photo), and riders reported experiencing a large snowpack collapse that they could feel while they were on their machines. This weak snow is preserved on middle elevation slopes on the shaded (north) side of the compass and on most slopes at upper elevations. I made a video yesterday to try to help explain where you will find this snow and why that is important, you can watch it here. I think it is worth your time.

    Weak layers like this are hard to deal with. They behave in ways that tend to catch even very experienced backcountry travelers off guard. Avalanches can be triggered remotely, from long distances below, above, or to the sides of steeper slopes. Avalanches that fail on this snow may pull back into gentler terrain above steep slopes thanks to the very dense slab of snow. Any avalanche that breaks on this weak snow will be very large, and likely unsurvivable. We are less than 24 hours out from the last snowfall, and this weak snow has hardly had time to start adjusting to its load. It won't take much to push it to its breaking point: that could be a collapsing cornice, a wind slab, or you. 

     

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    This week's storm delivered snow totals measured in feet and a healthy dose of wind to go along with it. This combination built thick, stiff drifts on many upper elevation slopes as well as in exposed terrain at middle elevations. Be on the lookout for these slabs and know that you are likely to trigger them when you find them. A sudden increase in snow depth and snow density are great signs that you are traveling through a wind slab. Cracks shooting out in front of your sled, bike, skis, or board are clear indicators that you've found an unstable slab. Large dunes, ripples, and textures on the snow surface, and freshly formed cornices all indicate that the wind has been at work.

    Wind slabs will be 1-3+' thick, easily large enough to bury you should you trigger one. These slabs are hazardous in their own right and are also adding weight to the persistent slab problem described above. If you find yourself traveling in an area where both of these problems exist I would strongly recommend that you rethink your choice of terrain.

Avalanche Discussion

CONSIDERABLE AVALANCHE DANGER Today, the Avalanche Danger is rated CONSIDERABLEon slopes at middle and upper elevations. This marks the first day in almost a week that the danger has dropped below HIGH. Over the course of this week, intense storms have hammered the mountains with heavy snowfall and wind and countless natural avalanches have occurred. Yesterday, the storm exited our area and the snowpack was able to start adjusting to this new load.

If you carefully read what I have written above you will likely find yourself thinking, "Wow, that sounds scary"! You may also find yourself wondering, "Why the avalanche danger is decreasing if conditions are so hazardous"? If you find yourself in that boat, let me try to make it a bit more clear. When we talk about Avalanche Danger we are talking about the likelihood of an avalanche causing damage to something of value. For us as backcountry travelers, this object of value is you, your friends, family, and your riding and skiing partners. When storms are adding weight to the snowpack the likelihood of both natural and human-triggered avalanches are greatest. When loading stops the snowpack can begin to adjust to the added weight, but this is a process that takes time. The likelihood of natural and human-triggered avalanches is slightly lower than it was yesterday, but the outcome remains the same.

Today, you are likely to trigger large avalanches if you enter avalanche terrain. These avalanches are likely to be large and unsurvivable. Please give the snowpack the time it needs and the respect that it deserves. 

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