Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

While the hazard rating has not changed, the avalanche danger has increased. Strong ridgetop winds have formed shallow pockets of wind slab in leeward terrain at the mid and upper elevations. These slabs could be triggered by skiers and riders on steep, wind loaded slopes. On a variety of aspects and elevations, the primary concern continues to be large to very large, human triggered persistent slab avalanches. Previous tracks are not an indication of stability with a persistent slab problem. Careful snowpack and terrain evaluation will be essential for safe travel in avalanche terrain.

Avalanche problems

  • Persistent Slabs

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

    Several weak layers of faceted snow can be found in the Teton snowpack, and they vary significantly across the landscape. Buried surface hoar and near surface facets, along with faceted snow surrounding crusts, are present in the snowpack. In the higher elevations, faceted snow that developed early in the season is deeply buried and rounding. While these deep layers are difficult to trigger, the resulting persistent slab avalanches have depths ranging from two to five feet and carry high consequences. Large triggers, such as snowmobiles, are more likely to trigger these deadly slabs. The basal weak layers are more easily impacted in the shallower mid elevation snowpack, and this problem extends down into the lower elevations. In these areas, slab depths are likely to be between one and three feet. Conservative terrain choices are the best tool to manage this hazard.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Westerly to northwesterly ridgetop winds increased into the mid-40s overnight with a max gust to 69 miles per hour. These strong winds transported the new and limited available snow onto leeward slopes, and shallow pockets of wind slab have formed. In localized areas, skiers and riders could trigger these slabs with depths up to a foot. Be wary of slopes with fresh deposits of wind driven snow.

Avalanche Discussion

High pressure will return tonight and inversion conditions are to develop by morning. Temperatures will start below zero in the valleys and in the single digits up high. By mid-afternoon, highs should reach the low twenties at all elevations. Winds are to be light to moderate from the northeast. The avalanche danger above 7500 feet will be Considerable in the Southwest Trails area and Moderate in the Teton and Togwotee Pass areas. Persistent weak layers lie within the snowpack. These layers lie under the past week’s snow and can also be found deeper in the snowpack, at varying depths including near the ground. The deeper layers are becoming less likely to fail, but if triggered could cause very large hard slab avalanches with depths to five feet. The presence of weak snow and therefore the likelihood of triggering slides is greatest in the Southwest Trails area. Below 7500 feet, the weak layers have generally combined, resulting in a snowpack with poor structure. In isolated areas, small slabs could still be triggered in very steep terrain.

Regions covered