Lawinenlagebericht

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

While not likely, you could trigger a 2-4 foot thick avalanche on some slopes. Unfortunately, slides could be very large and unsurvivable. You may be able to trigger avalanches remotely—from gentler terrain above, below, and to the sides of steep slopes. Picture where an avalanche would carry you before committing to skiing or riding steep slopes. 

Conditions are more dangerous in the Soldier Mtns and Dollarhide Summit area; refer to the Galena Summit & Eastern Mtns zone forecast.

Lawinenprobleme

  • Persistent Slabs

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

    What is it? You may be able to trigger a 2-4 foot thick avalanche on buried weak layers (sugary facets or crust + facet combinations). Hundreds of large natural avalanches released last week during the big storms. The likelihood of triggering a slide is decreasing, but the dense slab makes the consequences severe. 

    Where is it? This problem is worst on middle and upper elevation slopes facing W-NW-N-NE-E-SE. On slopes with multiple or thick crusts in the upper 2 feet of the snowpack, slab avalanches are much less likely. 

    How can you recognize it? Unfortunately, unstable slopes probably will not provide obvious signs of instability like snowpack collapsing or cracks shooting out in front of you. Snowpack stability tests are likely to be inconclusive and are of limited use. In low probability/high consequence situations like this, there's a good chance the first sign of instability you'll see is the avalanche you trigger. 

    How can you manage it?  You can reduce, but not eliminate, your risk by avoiding slopes steeper than about 35 degrees—especially large avalanche paths and those with ugly consequences if you are caught in a slide. The chance of triggering large avalanches appears to be highest on shadier, more northerly aspects. Persistent weak layers can fail unpredictably and break wider and higher on slopes than you might expect. You may be able to remotely trigger avalanches from gentler terrain above, below, or to the sides of steep slopes. Several people could ride or ski a slope before it avalanches; tracks do not mean a slope is guaranteed to be safe.

    ADDITIONAL DISCUSSION: 

    • While weather stations didn't record impressive winds in the past 48 hours, observers reported seeing some wind-blown snow. Also, E winds can form wind slabs in places you're not used to seeing them. Watch for thin, fresh drifts in upper elevation, wind-exposed terrain.
    • Despite the wintry weather, spring is officially here. As such, even brief periods of sunshine can be intense enough to trigger loose snow avalanches on steep, sun-drenched slopes. Rocky, protected areas with thin snowpacks less than a couple of feet thick are most suspect.

    (3/16/2023) These large avalanches released on NW and NE aspects at 6,700' in Deer Ck.

Avalanche Discussion

Most avalanche professionals would prefer to travel during HIGH danger driven by Wind Slabs rather than MODERATE danger due to Persistent Slabs. Why is that? Uncertainty. 

Managing the lingering but unpredictable Persistent Slab problem we're faced with is both frustrating and difficult at best. 

  • Following rare, powerful storms like those we experienced last week, slopes that don't avalanche can stabilize rapidly or at a snail's pace.  
  • If we look at 100 avalanche paths, triggering avalanches is not all that likely. But, triggering a large, unsurvivable slide could be very likely on one or more of those 100 paths.
  • We're unlikely to see signs of instability that clue us into which avalanche paths are unstable. We're not getting good feedback to help us figure out which slopes are the proverbial "loaded guns." 
  • The snow generally "feels good" beneath your skis or sled; you're not going to feel that "trap door" sensation of punching through into obvious weak layers. 

So what? Carefully consider the consequences of being caught in an avalanche before committing to skiing or riding steep slopes. If you could be carried through trees or buried deeply in a creek bottom or abrupt transition to flatter ground, the risk-reward probably isn't worth it. You can always choose to take avalanches out of the equation by staying off of and out from beneath slopes over about 30* in pitch. 

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