Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Mountain temperatures are starting out 10 to 15 degrees warmer than yesterday morning. Dense snowfall occurred overnight and southwesterly ridgetop winds were strong. This combination of weather factors, in addition to the recent snowfall, has created very dangerous avalanche conditions. Both human triggered and natural activity are likely today at the mid and upper elevations. Small to large wind slabs were easily triggered yesterday, and this trend will continue today. Faceted weak layers deeper in the snowpack continue to be loaded, and large to very large persistent slab avalanches will be possible. TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED. At the lower elevations, skiers and riders could trigger slab avalanches one to two feet in depth. These slabs could also release naturally.

Avalanche problems

  • Wind Slabs

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

    Snowfall totals since Wednesday are between 15 and 20 inches. Moderate to strong southerly to northwesterly ridgetop winds occurred during this time period, and dense wind slabs 12 to 30 inches in depth have formed on a variety of aspects. These reactive wind slabs reside just above firm sun crusts, surface hoar and near surface facets. Today, these slabs will continue to be easily triggered on steep, wind loaded slopes. Natural activity will also be likely.

  • Persistent Slabs

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

    One and a half to two inches of snow water equivalent has been added to persistent weak layers since Wednesday. Above 7,500 feet, this load has increased the likelihood of triggering dangerous slab avalanches with depths of two to four feet. These slabs could also step down from the release of a wind slab. The snowpack is comprised of mostly faceted snow below 7,500 feet. There, skiers and riders could trigger persistent slabs with depths of one to two feet.

Avalanche Discussion

The next system is to impact the area this evening and tonight. This could bring another seven or eight inches to the upper elevations of the Tetons by morning with the outlying areas and lower elevations receiving approximately five inches. Lingering snow showers will bring more accumulation and are expected to taper off through the day on Monday. Temperatures are to be cooler, with the mountains having highs in the low twenties. Southwest winds will be strongest during the snowfall with averages between twenty and thirty miles per hour. The general avalanche hazard is expected to be Considerable tomorrow. New snow will form new surface instabilities and could combine with the recently fallen snow to depths that could reach thirty inches in steep leeward terrain. These slabs could be triggered by a single person and could also release deeper weaknesses in the snowpack to depths to four feet at the higher elevations or to two feet at the lower elevations. Backcountry skiers and riders should exercise caution during this time of sensitive, dangerous conditions and elevated avalanche danger.

Regions covered