Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 9 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Mountain temperatures increased overnight and are starting out around 10 degrees warmer than yesterday morning. There were three reports of skier triggered slides yesterday with two people being caught and carried in separate events. These avalanches occurred on southeasterly through northeasterly aspects between 8,000 and 10,000 feet, were one to two feet deep and did not involve the persistent deep slab. Similar wind slabs are likely to be triggered today. Persistent deep slabs also remain a concern on a variety of aspects above 7,500 feet. Warming temperatures throughout the day may increase the likelihood of triggering these slides, and any extended periods of sunshine in the afternoon could exacerbate these problems on sunlit aspects. Conservative terrain choices will be the easiest approach to stay safe in the backcountry today. To find good skiing, seek out low angle terrain that is sheltered from the wind. Below 7,500 feet, skiers and riders could trigger isolated pockets of shallow slab in very steep, wind drifted terrain.

Avalanche problems

  • Wind Slabs

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

    Strong southwesterly to westerly ridgetop winds, warming temperatures, new snow and ample snow available for transport have all conspired to form wind slabs in leeward terrain. Since Thursday afternoon, 20 to 30 inches of snow has fallen in the mountains. Density breaks, sun crusts and buried surface hoar can all be found below these slabs. Skiers and riders are likely to trigger these 18 to 30 inch deep slabs in steep, wind-loaded terrain.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Since Friday the 19th, around three inches of snow water equivalent has been added to weak, faceted snow that formed during the December drought period. Large triggers, such as snowmobiles, are more likely to be able to impact this deeply buried weak layer. However, the weight of a single person could cause failure of these facets if a shallow trigger point is encountered. These slabs could propagate long distances, have depths to five feet and are likely to carry severe consequences to anyone involved.

Avalanche Discussion

The moisture that has been moving into the region in a northwest flow will decrease overnight. Skies are forecast to be partly cloudy on Monday. Temperatures will be in the 20s tonight and rise to near 30 at 10,500 feet and into the upper 30s in the valleys on Monday. Winds will be from the west to west-southwest and will decrease to 20 with gusts to 30 miles per hour.At the upper elevations of the Teton Range wind slabs with depths to 30 inches could be easily triggered by skiers and riders in steep wind loaded avalanche paths and cliff areas. Smaller wind slabs 8 inches to 2 feet in depth could be human triggered in similar terrain in the other forecast regions. Dangerous deep slab avalanches 3 to 5 feet in depth could also be triggered by snowmachines and or a skier in all of our forecast areas. Tomorrow's sunshine and warm temperatures are expected to increase the sensitivity of these slabs to human triggers. The general avalanche hazard is expected to be MODERATE in the Togwotee Pass area, the Greys River area and at the mid elevations of the Teton area. The hazard at the upper elevations (9,000 to 10,500 feet) of the Teton area is expected to be CONSIDERABLE.

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