Lawinenlagebericht

Tetons

Bridger-Teton Avalanche Center
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Lawinengefahr

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

Kernpunkte

It will be possible to trigger an avalanche 1-3 feet deep in steep, wind loaded terrain at the mid and upper elevations today. These slabs could be large enough to bury or injure a person. Carefully evaluate the snowpack for instability on steep, wind affected slopes and consider moving to sheltered, low angle terrain if you see cracking or recent avalanches. Avalanches are unlikely at the low elevations except in isolated pockets of very steep terrain.

 

Lawinenprobleme

  • Wind Slabs

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

    Wind slabs 1-3 feet thick were formed 48-72 hours ago above 7,500’ during a period of intense snowfall and strong winds out of the south and west. These slabs may be hard or soft and could still be triggered by the weight of a rider in very steep (>35°), wind loaded terrain. Given the recent high wind speeds, expect slab depths to be variable and to have formed further down and across slope than normal. The likelihood of triggering one of these slabs has decreased over the past three days, however human triggering is still possible today.

    Be on the lookout for unstable wind drifted snow while traveling in the mountains today. Recent avalanches, shooting cracks, and collapses in the snowpack are signs of instability. However, these signs may not present themselves before triggering an avalanche. Recent reports indicate that wind slabs were triggered after multiple people had ridden a slope. Additionally, the several inches of low density new snow may obscure surface clues of older slabs and require digging below the surface to verify their existence/reactivity. Avoiding very steep, wind loaded slopes is the easiest way to manage this problem today.

    (2/9/2025) 

    A wind slab triggered yesterday on Teton Pass. The likelihood of triggering these slabs has decreased over the past several days but is still on the table today.

  • Persistent Slabs

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

    Weak snow that formed during a dry period in the second half of January has been buried 3-5 feet deep by snowfall from the early February storms. These slabs sit on a variety of interfaces, including crusts on solar aspects and facets on shaded aspects. The likelihood of triggering slabs at this interface has decreased over time and is now on the low end of the scale. However, activating this layer may still be possible in very steep terrain. Large triggers such as a surface avalanche, cornice fall, or multiple riders on a slope will increase the odds of impacting these layers in the middle of the snowpack. While the chances of triggering are low, it remains important to stack the odds in your favor by following safe travel protocol. Travel one at a time across steep terrain, use islands of safety, and communicate with your partners.

Avalanche Discussion

A powerful winter storm beginning on February 6th brought about 2 feet of new snow and over 2” of water to the Tetons. Winds out of the southwest/west were notably strong during that time with gusts over 70 mph! As a result, wind slabs were formed on many aspects above 7,500’. On solar and mid elevation terrain, these slabs are sitting on a crust that formed during warm conditions around Feb 4th/5th and may be slower to stabilize than usual. These slabs were most reactive three days ago, but multiple avalanche reports from yesterday indicate that triggering a several day old wind slab is still on the table.

The Jan 31 interface consisting of crusts and facets remains on the radar, but is becoming less concerning. This layer has been buried by 5-6 feet of snow containing nearly 7” of Snow Water Equivalent (SWE). Since that layer was buried 7 days ago, temperatures have been warm, rain has fallen up to 9,000 feet, new snow and wind has stressed the snowpack, and temperatures have now cooled down. In summary, the snowpack has been put to the test by the weather as well as recent smaller avalanches within the newest snow. While observations have been somewhat limited due to poor visibility, the lack of reported activity at these depths, combined with these weather factors paint a picture of improving stability at this interface.

If you see avalanche activity today, please consider submitting an observation HERE. Observations allow everyone to gain a better and more complete understanding of conditions. Thanks!

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