Lawinenlagebericht

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Sawtooth Avalanche Center
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Lawinengefahr

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

The chance of wet snow avalanches will be highest this afternoon and evening in very steep, middle elevation terrain protected from the wind. Minimize your time on or under any steep slopes where you're sinking into a damp, sloppy snowpack. 

Lawinenprobleme

  • Loose Wet

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

    You can avoid today's wet snow avalanche hazard by staying off of and out from beneath very steep slopes (over about 35 degrees) where you're sinking into a wet, mushy snowpack. Last night's clear, cool weather allowed crusts to form on most slopes, but the snowpack is still soggy below the surface crusts. If your skis or boards are beginning to fall through the "trapdoor" into the damp snow, it's time to move to gentler slopes or areas with a more supportable snowpack.

    Where and when are we most likely to find a wet, unsupportable snowpack?

    • Middle elevation terrain: The frozen surface crust may not be as thick, and the combination of muted sunshine + warm ambient temperatures + plenty of terrain sheltered from the wind will help soften the surfaces. I expect conditions to be the worst/softest this afternoon and evening. You're most likely to find wet, unsupportable snow on shady and partially shady aspects (W-N-E-SE), especially near trees and glades.
    • At upper elevations, a harder freeze and breezy winds should preserve the surface crusts more so than at middle elevations. 
    • At lower elevations, the snowpack has disappeared or thinned dramatically on sunnier aspects. On more W-N-E facing slopes, wet avalanches will be possible this afternoon and evening.   

    Read the Forecast Discussion below for more information on wet loose avalanches, wet slab avalanches, and cornice failures. 

    (3/27/2022) This sizable wet snow avalanche occurred at 6:30 PM on Sunday, 3/27 in the Warm Springs Creek drainage. It started on a NE-facing slope at 6,500' and carried some large debris with it as it traveled down the slope. Photo: B. Smith

Avalanche Discussion

While the snowpack is nowhere near as wet and soggy as it was Thursday-Sunday, it's far from dry. The threat of wet snow avalanches is decreasing, but the residual wet-moist-damp snowpack deserves respect. Here's a look at the different types of wet issues you could encounter, in order of likelihood:

WET LOOSE AVALANCHES: These slides start at a point and fan out as they travel downhill. Slopes approaching and over 40 degrees in steepness will be most prone to wet loose slides. Most wet loose avalanches will be less than a foot thick, but these slides are deceptively powerful. Take a look at this photo of a slide that released naturally on Sunday evening at 6:30 PM in the Warm Springs Creek drainage. That avalanche had only about 500' to pick up steam, so you can imagine how large these can become in bigger terrain.

WET SLAB AVALANCHES: These are unlikely but can't be ruled out. Wet slabs occur when water percolates through the snowpack and weakens the bonds at buried weak layers while the slab above remains somewhat supportable. On Thursday, Ben spotted a large, destructive wet slab that released on an E/SE-facing slope at 9,700' in the Boulder Mtns. Yesterday near Baker Creek, Ethan saw that meltwater had reached the faceted layers about a foot deep on NW and NE aspects over 9500' in elevation. Accurately assessing wet slab stability on a slope scale is notoriously difficult.

CORNICES: Cornice failures are also unlikely but can't be ruled out.The recent heatwave caused these huge chunks of snow tocreep and sag downhill. This can cause the cornices to break off and tumble down the slope below. Once moving, the chunks can entrain large amounts of wet snow (photo) and trigger wet avalanches on the slopes beneath. Fortunately, they are easy to avoid by sticking to "terra firma" on ridgetops; make sure you're riding, sliding, or walking where rocks are showing through the snowpack or shallowly buried rather than on overhanging, car or bus-sized cornices.

Wet snowpacks can behave unpredictably, and water continues to move down through the snowpack. The likelihood of encountering wet snow avalanches is lower than yesterday, but the soggy snow below the surface crusts is keeping some uncertainty in the stability equation.  

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