Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 4 years ago.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

Highlights

Heavy snowfall and strong winds will stress the snowpack over the course of the day today. Triggering a large avalanche will be likely, especially where the wind is drifting snow.  Slides are also possible in steep, wind-sheltered terrain and at lower elevations. 

 

Avalanche problems

  • Wind Slabs

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

    Strong winds and heavy periods of snowfall will form touchy wind slabs on many slopes today. The added weight of windblown snow will also increase the probability of triggering a larger avalanche on a deeper layer. If you triggered a wind slab, it could "step down", failing on layers deeper in the snowpack and becoming much larger than the initial avalanche.  New snow slab depths will likely be 1+ feet in depth, particularly if the forecasted weather continues as predicted. Atmospheric river events are notoriously hard to predict with regard to precipitation types, amounts, and wind. Keep this in mind as you move in the mountains today. Pay attention to changing conditions, and remain conservative in terrain selection, particularly later in the day. 

    (12/26/2022)

    Snowpit on Mt. Glory showing weak snow that is about to gain a new slab today.

  • Persistent Slabs

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

    The November facet layer is buried about 3+ feet deep on almost every slope, with another layer from early December atop that (~1-2 feet deep). While there have been early signs that these layers are starting to strengthen—we're definitely not out of the woods yet.  It's important to come back to the simple facts: today we will gain a hefty slab on most aspects and elevations, which will be overlying known weaker snow. The best—and often only—way to manage a persistent slab problem (particularly with rapidly changing conditions) is by sticking to lower-angled terrain.

    Additional note: Above-freezing temperatures and light rain at low elevations will increase the danger of wet avalanches on slopes with saturated surface snow.

    (12/23/2022)

    Olive Oyl Pit showing low-strength ECTN (non-propagating) scores that may shift to ECTP (propagating) scores with incoming heavy snowfall.

Avalanche Discussion

With the array of recent avalanche accidents in the Tetons (Zero Space avalanche involving multiple parties outside JHMR boundary, Human-triggered avalanche on Taylor) and Greys River over the past month, I've been thinking a lot about every backcountry enthusiast's favorite four-letter word: luck. 

Any avalanche forecast is an inherently imperfect product. The grain we sand an entire mountain range down to (one rating and a few problems) is quite coarse. It rests on the shoulders of the user to continually utilize finer-grit sandpaper to apply to their decision-making and slope-specific terrain selection for the day. This is all the more true when conditions are changing rapidly, as they will today. As a community, we can reflect on accidents not with judgment, but with the awareness of how to refine our own habits and practices and continue to learn.  Luck will always come into play when traveling in the mountains. To a large degree, though, we can influence which way that pendulum can swing based on practicing consistent, good habits. Usually, these decisions are small (exposing one person at a time around steep slopes regardless of avalanche hazard rating) but can help cushion us from uncertainty.  No hunk of snow on a rock is worth a decision made in haste or a hackle raised but not mentioned due to social pressure. The mountains don't care whether we live or die; but we-your family, friends, and community-do.

Today will develop significantly differently than yesterday, and we need to exercise more conservative decision-making as this storm sets in. 

Regions covered