Lawinenlagebericht

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 7 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Weak layers of snow continue to make human-triggered avalanches possible today. You’re most likely to encounter unstable snow on upper elevation slopes with wind-drifted snow, but sheltered slopes demand your respect as well. Be aware that the weak layers in our snowpack are widespread and difficult to avoid.

Lawinenprobleme

  • Persistent Slabs

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

    Long lasting layers of weak snow are the name of the game this year. The character of these weak layers varies by aspect and elevation, but you can find them just about everywhere you look. The most widespread layer is a stripe of surface hoar that can be found in the lower to middle portion of the snowpack. This surface hoar has produced most of the human-triggered avalanches that have been reported to us this year. In addition, weak snow near the ground exists on many middle and upper elevation slopes. 

    Persistent weak layers present a complex and frustrating problem for backcountry travelers. They can continue to produce avalanches many weeks after they are buried and they provide fewer and fewer obvious signs of instability as the days without a major loading event pass. They can break wider than you might expect and may be triggered remotely, from gentle terrain adjacent to steeper slopes. Read about my thoughts on how I deal with this type of problem in my personal travels in the Forecast Discussion section found below.

    Additional Discussion

    I traveled through upper elevation terrain on Galena Peak yesterday to get a closer look at the recently formed wind slabs. I experienced some localized cracking in these slabs, particularly where they were sitting on stiff, icy surfaces. And, even though these slabs were posing a hazard in their own right, that was a bit of a moot point. I found that the underlying persistent slab problems described above were keeping me out of the terrain where I might have been able to trigger a wind slab.

Avalanche Discussion

We are back to that point where we are talking about likelihood and consequences. I understand, for a lot of you it isn’t the most exciting topic. But humor me here, I think it's worth your time. Take a minute, pour a bit more coffee, and follow me through this thought exercise:

What is the likelihood that you are traveling on a slope with buried weak snow? That’s pretty simple this year - it's very likely. What are the consequences of traveling on such a slope? Well, if you are avoiding avalanche terrain, there aren’t any negative consequences. However, if you are in avalanche terrain, the consequences of triggering and being caught in a slide would be quite high. Continued snowfall and wind loading are creating an increasingly thick slab on top of the weak snow underneath. As the slab grows its potential destructive power increases.

But here’s where it gets tricky: What is the likelihood that you might trigger an avalanche on a buried weak layer if you are in avalanche terrain? Well...it’s possible. There are plenty of places where you might trigger a slide and plenty of places where you might not. As I skied yesterday with a friend visiting from out of town I explained this problem to him. I pointed out steep, enticing slopes covered in fresh, soft snow that would have undoubtedly provided us with some fantastic skiing. But we didn’t do anything more than daydream about them. Didn’t even think about it. We avoided avalanche terrain with buried weak layers; not because we thought triggering a slide was likely, but because we knew it was possible.

We skied great snow in low angle terrain, free from the hazards posed by our persistent weak layers. For me personally, the overriding goal is to come home safely at the end of each day. After all, I can’t go skiing tomorrow if I don’t make it out of the mountains tonight.

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