Lawinenlagebericht

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Lawinengefahr

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

You could trigger a slab avalanche on upper elevation slopes where the wind formed drifts during the recent storm. The chance of wet avalanches will increase with today's sunshine. Watch for the newer snow becoming moist and sliding on slick crusts. Near valley bottoms, expect to find wet, rotten snow by this afternoon. 

Lawinenprobleme

  • Wind Slabs

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

    During the recent storm, the Sawtooths & Western Smokys received the most snowfall (6-10"+) along with moderate to strong winds. Professional observers in the Sawtooths reported a natural wind slab avalanche yesterday. Increasing NW winds last night may have formed a new round of wind drifts. Triggering a wind slab in this zone is a real concern, and they could be large enough to bury or injure a person.

    It's been a while since we've been concerned with dry snow avalanche problems. Even if your winter avalanche eyeballs are a bit rusty, these fresh wind slabs should be easy to identify today. If you find hard crusts blown free of snow, ask yourself where that snow went. Look for pillowed or drifted areas on the lee sides of ridges, gullies, and other terrain features. In terrain like the Sawtooths, wind slabs often form along the sides of couloirs and on aprons below cliffs.

    ADDITIONAL DISCUSSIONObservers have reported that the newer snow is sluffing easily—watch for dry loose avalanching on very steep, northerly-facing slopes.

    (3/19/2021) On Friday, moderate to strong winds were transporting the new snow and forming wind slabs at upper elevations.

  • Loose Wet

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

    It was a relief to see clearing skies this morning along with below-freezing temperatures from mountain tops to valley floors. This was a much-needed change, especially for our rain-soaked low elevation snowpack. Although the snow surface will begin the day on lockdown, expect an increased likelihood of wet avalanches as the sunshine warms solar slopes and low elevation temps climb above freezing. Broadly speaking, you're likely to encounter two types of wet snow problems as the day warms up:

    • As the sunshine heats solar aspects at middle and upper elevations, the newer snow will become moist and tend to slide off the old crusts below. You can test small, steep slopes by pushing on the surface and checking to see if the newer snow peels off the crust and runs downhill. Natural wet slides may become possible later today, so pay attention to overhead terrain and don't linger beneath steep, sunny slopes.
    • At lower elevations, recent rain and wet snowfall lead to a saturated, rotten snowpack. With clear skies and below-freezing temperatures overnight, conditions this morning will be much improved. But as the surface crust thaws today, you may once again find yourself sinking into a bottomless mess. 

Avalanche Discussion

While triggering a large avalanche is unlikely today, there are a number of places where you could trigger smaller slides—and these could come in a number of forms. So even though the avalanche danger is LOW (MODERATE in the Sawtooths & Western Smokys, where these problems will be more likely), traveling in the backcountry today will necessitate keeping your head on a swivel from the valley floor to the mountain tops.  With that in mind, I present to you:

4 SIGNS YOU'VE STUMBLED UPON UNSTABLE CONDITIONS

  1. While skiing/boarding or sidehilling your machine on a steep, sunny slope, the newer snow starts peeling off the old crust and sliding downhill. It doesn't seem like much at first, but it starts to gain mass and momentum as it runs downhill. You just triggered a WET LOOSE AVALANCHE involving the new snow, and you're glad it released below you.
  2. You've been finding about 4-6" of newer snow in sheltered terrain, but suddenly find yourself on a wind-exposed slope with nearly 12" of slightly denser, dry snow on it. Cracks shoot out from your board(s) or machine, and you've realized you just found a WIND SLAB. Good thing you're on a low-angle slope!
  3. You're riding a north-facing, 40-degree chute and realize that the cold, dry surface snow is starting to move with you. Your first thought is to get rad and go faster, but you come to your senses and cut off to the side of the slope as the DRY LOOSE AVALANCHE continues to sluff downhill. 
  4. Towards the end of the day, you and your partners are exiting through lower elevation terrain. You've been discussing the close calls you've already had, but—hey—they've been small problems that wouldn't have buried anybody. Suddenly you find yourself sinking to the ground into a rotten, wet, isothermic snowpack. You look up at the steep slope overhead and become concerned about natural WET AVALANCHES. Time to move!

Be sure to catch up on what happened in our latest weekend update.

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