Lawinenlagebericht

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Sawtooth Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
4 · Gross
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Veraltet — dieser Lagebericht ist 7 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The combination of new snow and wind is creating dangerous avalanche conditions. In terrain exposed to the wind, fresh slabs will be large and easy to trigger. This additional load is also adding weight to older weak layers, buried 1-4 feet deep in the snowpack. Both human-triggered and natural avalanches are likely today and travel in avalanche terrain is not recommended.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1–2

    The wind slab portion of the avalanche problem is pretty simple today. Over 2’ of low density snow has fallen in favored portions of this zone. Winds are easily transporting this new snow into thick drifts. As you gain elevation, you will be more and more likely to find these slabs and they will grow in thickness and distribution. They will be most sensitive in upper elevation terrain where winds are strongest and the winds are transporting the most snow.

    Yesterday, I was up high in the Smoky Mountains when the wind speeds increased. At upper elevations, the wind was quickly building slabs out of the low density snow that fell in the past two days. I found that these slabs were sensitive to my weight and I avoided avalanche terrain. As I skied back down, I found that much of my skin track had already been buried by wind drifted snow. When I returned to my sled on the valley floor, I could see that even at lower elevations the wind was moving snow.

  • Persistent Slabs

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

    Don’t let the new snow distract you from the other issues we have to deal with in our snowpack. Pick a slope, put your shovel in the snow and you’ll be likely to find at least one of the buried weak layers we’ve been worrying about all season. Surface hoar, depth hoar, crusts with facets — you name it, we’ve got it. Although the nature of these weak layers varies across our forecast area, their presence on any given slope is almost guaranteed. 

    As the storm rages on these layers are being pushed to their breaking points. Now is not the time to be testing the sensitivity of these layers with your skis, board or machine. Stick to gentle terrain not threatened by avalanche hazard from above.

Avalanche Discussion

Buried persistent weak layers in the snowpack are notoriously difficult to deal with — both as a backcountry traveler and an avalanche forecaster. We have a complexly overlapping pattern of these layers in our snowpack right now, which doesn’t make things any easier. If you haven’t been paying attention to an individual slope throughout the season, predicting what weak layers might exist there and how reactive they might be is nearly impossible. Doing it by highmarking or center-punching a slope is a game of Russian Roulette. 

Performing snowpack tests can help us to understand where these sorts of problems are at their worst, but predicting the exact timing of avalanche activity on these layers is nearly impossible. Starting on Friday, an active weather pattern brought periods of intense precipitation to our area. As of this writing, 1-2’ of snow have fallen and its actually starting to look like winter out there, a welcome change of pace. However, this intense loading event is stressing the weak layers that exist throughout our forecast areas. Lipstick on the pig, as they say.

In life and in the backcountry, it's important to recognize when you are dealing with an unpredictable problem. How will the weak layers in our snowpack react to this sort of a loading event? The unsatisfying but truthful answer is that we just don’t know. But, I can tell you with certainty that the likelihood of triggering a slide on one of these layers is increasing as the snow stacks up. 

Today isn’t the sort of day to go out and make decisions about what slope you are going to play on based on stability tests. Mother nature is in the middle of performing her own stability test — we won’t know the results until the sky clears.

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