Bollettino valanghe

Tetons

Bridger-Teton Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Today’s avalanche danger will rise to Considerable with sunshine and warming temperatures. You're most likely to trigger an avalanche on steep, upper-elevation slopes where wind has affected recent snow.  If you find stiff drifts or shooting cracks, move to more sheltered slopes. If you see signs of changing conditions, such as rollerballs or slushy snow, move to colder aspects and watch out for steep sunny slopes above you that might be warming faster than you expect.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Slabs up to 2 feet exist on all aspects at upper elevations in wind-affected terrain. Recent northwest winds have loaded south through east aspects. However, it is still possible to find this problem in cross-loaded terrain on other aspects. Various crusts and weak interfaces exist in the top few feet of the snowpack and slabs may break bigger than expected.  Keep an eye out for stiff pillows, hollow-sounding drifts, and cracking around your skis. Larger or older slabs may not present any clues before it's too late. While unlikely, wind slab formation may have crept down into middle elevations in very exposed terrain above 8500 feet.  Multiple reports of natural and human-triggered wind slabs from the last two days are evidence of this problem. As the day heats up, the sensitivity of these slabs will increase. Avoid steep wind-affected terrain near ridges, below cliffs, and in crossloaded terrain features.

    Minimize time spent under cornices. These can break unexpectedly and are more sensitive to warming temperatures. Cornices can act as large triggers and impact deeper weak layers.

    (4/1/2024)

    Upper-elevation wind slab with active wind loading

    Photo: Teague Holmes

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Wet loose avalanche activity is possible on most steep slopes that see the sun.  While the Tetons have already gone through a significant wet loose cycle that started on 4/1, increasing temperatures will keep this problem on the radar. The hazard will increase throughout the day with warming temperatures and solar input, starting on southeast aspects and moving to south and southwest as the day progresses. Snow near warming rocks will be sensitive and it will not take long for snow surfaces exposed to the sun to become moist. Watch for rollerballs and pinwheels as the day warms and look for activity starting in the morning hours. If snow becomes slushy, it’s time to move to shadier aspects. Watch your overhead hazard as steep slopes warm above you. These avalanches can run far and entrain large amounts of snow - a potentially hazardous situation if you are traveling in the bottom of a drainage with south-facing slopes above.

    (4/2/2024)

    A fairly large loose snow avalanche on the SE facing side of Mt. Wister. This avalanche has both storm slab and wet loose characteristics which is typical of springtime warm ups after a storm.

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

We are a day into some warm and sunny high pressure following several days of snowfall and high winds in the alpine.  The day will start out with some crusty early morning snow on anything that was exposed to the sun and most slopes below 8500 feet. Dry snow remains on shady slopes above 9000 feet. The April sun will cause rapidly changing conditions and increase the hazard throughout the day.

A few considerations:

  • Natural avalanches are still possible - be aware of steep overhead hazard above you as you ride and minimize time on exits that travel through tight drainages (terrain traps).
  • Steep southeast slopes will warm first followed by south and then southwest. Plan your day accordingly and be off or out from underneath those slopes in that order as things warm.
  • Rapidly changing conditions require route and time planning and warrant conservative decisions. Anticipate and adjust your plan if you see things changing sooner than expected.
  • Wanna geek out and practice some navigation skills? Great, keep reading, otherwise stop here. Get out your mapping software of choice and draw your intended route. Choose some waypoints along the way and estimate how long it will take to get there. There are a few ways to estimate how long route legs will take including a Munter rate calculation if you are on foot/skis. It's worth a search on the interwebs if you are unfamiliar with it and will help with time planning. Some mapping software even integrates this tool when route planning. Does your route put you on or traveling through steep sunny slopes after 10 am? Verify your time plan at the end of the day and see how close your actual time was to your estimate.  Don't forget to add in your snack breaks.

Help us improve avalanche forecasts! CLICK HERE to take an avalanche forecast survey and be entered into a prize drawing. The Colorado Avalanche Information Center, the Avalanche Research Program at Simon Fraser University, and the U.S. National Science Foundation National Center for Atmospheric Research are researching how skiers, snowmobilers, snowshoers, ice climbers, and anyone else who travels in the backcountry interpret avalanche forecast information. Part of this research includes a specific survey to better understand how useful avalanche forecast information is for trip planning. 

Completing this survey will take approximately 20 minutes. Thank you for sharing your feedback to help us improve avalanche hazard communication. 

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