Lawinenlagebericht

Tetons

Bridger-Teton Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Kernpunkte

The avalanche danger will rise throughout the day. Incoming snowfall and strong winds could create dangerous avalanche conditions in middle and upper elevation terrain by the afternoon. Human triggered avalanches will be likely in steep, wind loaded terrain. Carefully evaluate new snowfall amounts and watch for signs of instability such as cracking. Sheltered low angle slopes will provide the safest riding today.

Lawinenprobleme

  • Wind Slabs

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

    Heavy snowfall is expected to develop in the Tetons by midday. Nearly a foot of snow containing about 1” of snow water equivalent (SWE) could fall by evening. Ridgetop winds at 10,000’ are averaging around 40 mph out of the southwest at 5 am and are expected to increase throughout the day. If the weather forecast verifies, expect sensitive new slabs up to 2 feet in depth to form in exposed middle and upper elevation terrain by the afternoon. Given the intensity of the wind, watch for slabs to form further below ridgelines than expected. In some places, these new slabs could form on top of existing wind slabs formed over the past few days. Slab depths will be greater in terrain where this occurs. Careful snowpack evaluation will be important today. If you observe significant new snowfall (greater than 4-6”) and windy conditions, then it is safest to steer clear of steep terrain and seek low angle, sheltered slopes. 

    Cornice Falls: Observations of cornice failures continue to be reported. Give cornices a wide margin and be careful along ridgelines as they can break further back than expected. Falling cornices can impact deeply buried weak layers and trigger large avalanches.

    (2/24/2024)

    A wind slab that caught and carried a skier 500 feet in Grand Teton National Park.

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    1.5–2.5

    Hard slabs 3-5 feet thick overlay weak snow that formed earlier in the season. Steep, rocky, unsupported, and wind affected terrain on the north half of the compass has proven itself to be most suspect. Thin spots (trigger points) in the slab are most common in these locations. While it has become unlikely for a human to trigger one of these slabs, the significant snowfall and wind expected over the next few days will stress these weak layers and make them more susceptible to triggering. Large triggers such as cornice falls, smaller avalanches, or even snowmobiles still have the potential to impact weak layers buried deeply in the snowpack. Extra caution is advised in terrain where problem #1 and #2 overlap.

    The last avalanche involving persistent weak layers was triggered by a large cornice fall on 2/21. The last human triggered avalanche on these layers occurred on 2/10.

    (2/17/2024) Photo: Teton County SAR

    A very large persistent slab avalanche that occurred on No Name Peak after a period of significant loading.

Avalanche Discussion

There is a good deal of uncertainty regarding the timing of the incoming storm. It is possible that the storm hits later than expected. If this happens, avalanche conditions will be less dangerous during the day. On the other hand, it is possible that the incoming storm hits hard at midday. Avalanche conditions in the afternoon will be dangerous if this option pans out. It will be very important to evaluate the snow conditions for yourself today. Thankfully, it is a fairly straightforward decision. If it is snowing and blowing, then expect avalanches in steep terrain. If it’s just windy, then be on the lookout for drifted snow in steep, exposed areas. Given the uncertainty in the weather forecast it is best to make a conservative tour plan and give yourself safe options if conditions deteriorate.

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