Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Firm wind slabs in the upper elevations remain the primary avalanche concern. Look for isolated terrain features where wind has deposited snow creating drifts and stiffened surfaces. Although less likely, triggering deeper slabs on weak layers buried 2-3 feet deep remains possible. Keep an eye on changing snow instability as temperatures increase throughout the day. 

Yesterday a skier triggered a D2 avalanche south of JHMR above No Name Canyon while riding complex terrain, carrying them over cliffs and requiring a full helicopter rescue from TCSAR. 

 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Snow from Feb 8th has been accompanied by moderate to strong primarily westerly winds of varying direction over the last several days creating firm, cohesive slabs. Most slab will be less than a foot deep, but could be up to 2 feet deep in heavily wind deposited terrain. These slabs will be confined to the upper elevations mainly on easterly aspects in areas with obvious wind effect in the form of scoured and deposited snow. Look for these slabs on exposed ridgelines, above cliff features and confined spaces such as couloirs. The avalanche yesterday on No Name Canyon has not been investigated, but appears to have some influence of wind slabs based on photos and proximity to the ridgeline.  

    Monitor rapidly changing conditions as rising temperature throughout the day increases the overall reactivity of the snowpack. Look for obvious signs of instability such as wet surfaces, rollers, and natural point triggers. Wet loose activity could be seen in specific terrain features on southerly aspects near cliffs and rocks. 

     

    Wind slab avalanche on No Name Canyon where a skier was caught and carried requiring rescue from TCSAR.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–2.5

    Buried weak layers continue to haunt our snowpack. Avalanche activity on these layers has decreased over time, but the poor structure still exists with propagating test results in snow pits. The primary concern is the Jan 26th layer buried 2-3 feet deep, which varies across aspects and elevations as crusts and/or weak, sugary facets. This low probability, high consequence type of avalanche problem is difficult to manage. Areas with a shallower snowpack generally have a weaker snowpack that should be a concern due to the trends of human triggered avalanches this season. Dig down and identify these weak layers before committing to complex and consequential terrain. 

    Deep Persistent Slab: In addition to persistent slab problem type, a  deeper weak layer persists in middle and upper elevations on southeast through west aspects. These layers appear to be dormant but could awaken with a big storm or large load, such as another avalanche. The resulting avalanche could be up to five feet thick and carry severe consequences. 

    (2/11/2023)

    Teewinot 10,300' SE aspect. Snowpit where we experienced large collapse. No cracking. Great example of why to avoid thin, shallow areas. 

    Photo: Drinkard

Avalanche Discussion

The forecast area has not seen any new snow since Feb 8th, yet human triggered avalanches are still occurring. This is due to the fairly widespread wind effect in the upper elevations that has created reactive wind slabs in isolated terrain. As good weather continues, skiers and riders are venturing into more obscure and hard to reach terrain. This is a natural progression as backcountry users gain knowledge of the snowpack and expand their terrain choices. Fresh tracks also become more elusive. Don’t let these human factors cloud your judgment though. Stay humble and remember that new terrain requires a new perspective. The variability of our current snowpack requires constant reassessment in new terrain, with a high amount of uncertainty in snowpack structure within all three forecast zones. Look for those avalanche problems described above as you travel through terrain, dig down in the snow, and monitor the snowpack during changing conditions such as increased temperature. 

 

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