Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Recent snowfall and warming weather make avalanches likely today. Numerous large natural and human-triggered avalanches were observed yesterday. Stability will deteriorate faster on very steep, sunny slopes, but will not be limited to these areas. Triggering a larger avalanche breaking deeper than expected is possible on more shaded, cooler slopes at middle and upper elevations. Plan an early start and be ready to move to gentler terrain free from overhead hazards as the day progresses. 

Avalanche problems

  • Storm Slabs

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

    The Tetons received 6-10+ inches of snowfall a day ago, which remains very reactive and is also experiencing a rapid temperature change. Additionally, various crusts and weak interfaces exist within the top three feet of the snowpack that have remained untested until now and hold the potential to craft a larger avalanche. They will be more prone to human triggering over the next several days as each day as more sunshine continues to impact slopes and temperatures increase. As the day heats up, more slopes will become unstable. The new snowfall may not feel wet or mushy, especially if traveling at or above 10,000 feet. However, increasing temperatures still impact aspects holding dry snow as surface snow gradually melts and breaks down. Today's transition from dry to moist will happen quickly (and subtly on shadier aspects). Be prepared to adjust your plans accordingly.

     

    (4/1/2024) Photo: Teague Holmes

    This large avalanche was observed yesterday up Garnet Canyon near the South Teton.

  • Loose Wet

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

    Wet snow avalanches are likely, and the threat of natural and human-triggered avalanches will quickly increase as the day heats up. Many of these avalanches will run as point releases and loose snow avalanches, and some south-facing high-elevation features may produce avalanches of new snow that span the divide between a storm slab and a wet problem. Periods of clouds can press the pause button on this type of slide, but it doesn't take much March sun to melt the snow. Initially, these slides may have more of a dry character. The upper bit of the snow will melt and send the dry snow underneath, cascading down the slope. As the day warms and the sun melts deeper into the new snow, the debris from these slides will become wetter and more destructive. This problem will follow the sun, starting with E/SE aspects and wrapping around to S and W as the sun moves across the sky. Give steep overhead slopes a wide margin as the day warms. Pack it in early and give yourself options, including safer, low-angled options and exits not threatened from above by cornices or steep sunny slopes. Any prolonged period of sun will increase the likelihood of avalanche activity significantly, and early morning slab problems on S upper elevations may transition to wet problems later in the afternoon. If sinking into a mushy snowpack, find cooler snow or stick to lower-angle slopes.

Avalanche Discussion

It might've just been April Fool's Day, but the current avalanche problems are no joke. Nearly every problem in the book will be present today. As you venture out, be aware of various conditions, from wet snow problems to dry snow problems, and regard this snowpack as you would a mid-winter snowpack.

Observations so far (knowns):

  • Numerous storm-related avalanches have occurred, many breaking deeper than folks expect.
  • Enough avalanches have occurred to start to pick apart a pattern and how long it will exist and continue.
  • Warming temperatures will mean new snow will start to span the divide between dry-moist-wet problems.

Observations needed (unknowns):

  • Will upper-elevation southerly slopes all run as wet loose, or will those pesky slopes above 10,500 that still hold cold snow border on a "moist storm slab" problem?
  • Will additional observations of avalanche activity show slides breaking deeper than the newest snowfall on weak snow buried in late March?
  • Will increasing temperatures over the next two days resolve instability quickly, or will many upper-elevation slopes that remain cool hold lingering problems for longer than we expect?

With new snow problems and tropical temperatures, I wait until the "knowns" list is longer than the "unknowns," embrace a wait-and-see-what-pans-out attitude and dial back my terrain choices.

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