Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Heightened avalanche danger exists in steep wind-loaded terrain where triggering a large avalanche up to 2 feet thick is possible. In very steep, heavily wind-loaded slopes at upper elevations, avalanches could break deeper than expected. Evaluate steep terrain carefully, especially around cliffs, couloirs, and other wind-loaded features. Consider the consequences of getting caught and carried into unforgiving terrain.

Yesterday,  multiple skier-triggered avalanches were reported, including a large D2 that caught and carried a skier several hundred feet. The skier was partially buried and thankfully uninjured.

Avalanche problems

  • Wind Slabs

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

    It remains possible to trigger a large windslab 1-2 feet deep in very steep wind-loaded terrain above 8500’. In places that are heavily wind-loaded, avalanches could break deeper than expected. Increasing southwest wind combined with several inches of snow today will increase the danger in wind-loaded areas. Look for drifting snow and cracking snow surfaces today as evidence of unstable snow.  Keep in mind, however, that signs of older slabs are now hidden in places, and you may not see visible warning signs like shooting cracks or obvious drifts. These older slabs exist on multiple aspects, based on changing wind directions earlier this week. Carefully evaluate steep slopes for evidence of firm wind slabs underneath recent snow. Giving very steep and wind-loaded features like cliffs and couloir entrances a wide margin is the best way to manage this problem today. 

    The 18-24 inch crown of an avalanche in wind-loaded terrain that caught and carried a skier yesterday on the West side of the Tetons.

    Thanks for sharing this observation!

Avalanche Discussion

The upper Tetons received over 50 inches of snow and about 5 inches of water this week, combined with temperature fluctuations and lots of wind from the southwest, west, and northwest. This combination created several poor interfaces that remain reactive, with much higher consequences in wind-loaded areas where recent avalanches have been large enough to bury riders.  In heavily wind-loaded areas at upper elevations, the crust that was buried on 3/13 is up to 3 feet deep with a stiffening slab on top. This crust interface, as well as shallower storm density breaks, have continued to produce avalanches. The good news is that the poor interfaces are likely gaining strength, aided by settlement, but this process takes time. 

Managing this windslab problem will require identifying where the wind has deposited snow this week and considering that slab depths in some areas may not be conducive to your typical wind slab mitigation techniques. These slabs may or may not break at your ski tips and may not show warning signs beforehand. Investigating these interfaces before committing would be prudent. Entering this specific terrain (upper elevation, wind loaded) with a more conservative mindset and considering consequences might also be a good approach while we give the snowpack a little more time to adjust.

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