Lawinenlagebericht

Tetons

Bridger-Teton Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

To reduce the chance of triggering avalanches, avoid slopes where the wind recently formed drifts or slabs. In areas more protected from the wind, triggering a 2-3 foot thick avalanche is possible. An incoming stream of new snow will continue loading buried weak layers. Pay attention to the consequences of being caught on even smaller steep slopes or terrain with rocks, cliffs, and trees.

Lawinenprobleme

  • Persistent Slabs

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

    This zone has persistent weak layers buried 2-3 feet deep on most middle and upper-elevation slopes. The 3/20 interface can be found in hand pits and full pits and it will behoove you to assess it if entering avalanche terrain in the backcountry today. There's no magical formula, but the most important factor we have on our side is time. It's been two days since the snowpack has been significantly stressed by new snow, wind, or major temperature fluxes. Imagine how you'd feel after two days on the beach with no email, no texts, and no news: probably pretty good, but you'd want more time there. Having more time is good for both you and the snowpack—but this problem is still very much present. The most important fact to note is that avalanches are being reported daily on this interface, and most of these show wide propagation across slopes and terrain features. More snowfall overnight tonight and into Thursday will test these layers. Persistent slab avalanches are unpredictable on the best of days—and believe me, the land mines out there exist. 

    ADDITIONAL DISCUSSION

    With skies remaining overcast and little incoming precipitation today, avalanches on steep slopes at low elevations are less likely. If this storm produces enough moisture over the next 72 hours, rain and warm midday temperatures may start to peel snow off of these areas in the form of wet avalanches.

    (3/28/2023)

    4 avalanches were noted in Teton Canyon yesterday. These natural avalanches showed wide propagation and were large enough to injure or bury a person. 

  • Wind Slabs

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

    The wind has plenty of ammunition in the form of new snow available for transport to craft slabs. Expect to find some stiff or hard wind slabs in exposed terrain, and some of these may remain reactive and be buried beneath further snowfall over the next several days. Monday night's new snow and wind produced some natural avalanche activity, and stronger winds today could continue building slabs. Though not huge, these wind slabs could be sensitive to your weight and are stressing the buried weak layers described in Problem 1 above. The easiest way to avoid this hazard is to recognize this problem and avoid slopes steeper than 35 degrees. If you see cracks shooting out from your skis or sled or feel hollow, drum-like, or chalky snow, you've found a wind slab. 

    It is worth noting that continued snowfall into the spring will build cornices that may behave in unpredictable ways. Steer clear of being beneath or directly above these features; skin or sled on rocks, trees, and whatever clues you into the fact that you are anchored to the ground, and not floating on the back of one of these monsters. 

    (3/27/2023) Photo: Antonioli

Avalanche Discussion

In my earlier years, the question I often asked before committing to avalanche terrain was, "Do I think this is going to slide?" If I thought the answer was no, I went for it. This process felt pretty simple, especially in areas I skied frequently and felt I "knew." I knew the conditions under which X  or Y slope would avalanche. If those conditions weren't present, it made answering that question all the easier. But asking this question left such a small margin for error because whether or not a slope is going to slide is a tough one to accurately answer. I also answered this question wrong a few times.

Over many years, you see snow behave in a lot of strange ways that surprise you. I've realized that question isn't possible with an acceptable level of certainty. The other day, standing next to a steep slope at Togwotee with my partner, we asked a subtly different question, but that difference is important. "Would we be totally surprised if this thing avalanched?" This question is more conservative and takes into account the uncertainty faced when dealing with a tricky snowpack.

So do I think someone will trigger a slide today? No. But would I be totally surprised if someone does? The answer is also No. As time has passed and my avalanche knowledge has increased, I've ridden less steep terrain—not more. When I do ride steep terrain, I enjoy it more knowing that I am more confident in my decision and that I'm exposing myself to less risk.

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