Lawinenlagebericht

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Lawinengefahr

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

Kernpunkte

You could trigger a 1-3 foot thick slab avalanche on very steep, wind-affected slopes. These slides are most likely at upper elevations where recent strong wind formed stiff drifts. To reduce your risk, steer clear of obviously wind-loaded terrain where the snow surface is hard.

Lawinenprobleme

  • Persistent Slabs

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

    The Soldier & Wood River Valley zone has been "spared" the recent snowfall that's fallen further north, but who needs snow when you have wind? Extreme wind events this past week “repurposed” snow from windward slopes and deposited it into thick, hard, wind slabs. In many areas, these 1-3 foot thick slabs sit atop weak, sugary facets in the lower portions of the snowpack.

    Triggering a slide on one of these weak layers is unlikely. However, if you were on a mission to find one, here's where I would look: exposed, wind-loaded terrain steeper than about 35 degrees, including cross-loaded gullies lower on slopes.

    If the snow surface is hard or you see cracks shooting out from your skis or sled, it's time to pay attention. Picture where an avalanche could carry you before committing to skiing or riding exposed avalanche terrain—the consequences of a triggering a powerful persistent slab should not be taken lightly.

Avalanche Discussion

As we enter the first period of stable weather in quite some time, it's a good time to do a "State of the Union" on our current snowpack. 

The Soldier & Wood River Valley snowpack is the shallowest and weakest, especially in the mountains above Ketchum and Hailey. As is not uncommon in this area, there is plenty of weak, faceted snow—what's lacking is a slab of cohesive snow atop it. Unstable slopes are largely limited to where recent and/or past wind events have created dense or stiff snow in the upper pack. This was the case with a slide triggered during control work last week on Baldy. Storms earlier this winter favored the western half of this zone, and the snowpack there is more similar to Galena Summit.

The deepest snowpack exists in the Sawtooth & Western Smokys and Banner Summit zones. While these areas had thin snow at the start of the winter, they were heavily favored by the extended storm cycle at the start of the New Year. The early season weak layers are buried 4-6 feet deep, meaning that triggering an avalanche is difficult but likely unsurvivable. Avoiding thinner "trigger points" is the name of the game—these are more likely to be found in very steep, rocky, alpine terrain that is prevalent in the Sawtooths but less so in the Banner Summit area.

Finally, the Galena Summit & Eastern Mtns zone is the monkey in the middle. There is a great deal of variability across this zone, but it all falls somewhere between the two scenarios described above. The thin, windswept snowpack of the Boulder and Pioneer Mountains has characteristics of the Wood River Valley, where wind slabs sitting atop weak, faceted snow are the main concern. The Smoky Mtns of Galena Summit and the Baker Creek area have a bit deeper snowpack, with early-season weak layers buried 2-4 feet deep. In the White Clouds, the faceted snow near the ground seems especially pronounced—just a week ago, a monster broke over 500 feet wide and 4-6 feet thick.

So there you have it—the current State of the Snowpack. Just don't rip it in half...

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