Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
View on map

Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 7 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A large slab avalanche that failed on faceted snow at the base of the snowpack was triggered by skiers yesterday. Similar events are possible today. These large slab avalanches can be triggered on steep avalanche prone slopes at the mid and upper elevations. They can be triggered by the weight of a single person and on slopes with tracks. These dangerous slides will fail on a weak layer of faceted snow that persists near the base of the snowpack. This weak layer is easy to find if you dig down through the snow to the ground. If this layer is present in avalanche prone terrain, conservative terrain choices are warranted. Avalanches are unlikely below an elevation of 8,000 feet.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Large persistent slabs avalanches up to four feet in depth can be human triggered on steep slopes at the mid and upper elevations. These slabs are mostly likely to be triggered by skiers, snowboarders and snowmobilers on northeast through northwest aspects between an elevation of 8,000 and 9,500 feet but could be triggered on east through north to west aspects at those elevations and on a variety of aspects above an elevation of 9,500 feet. Weak faceted layers near the base of the snowpack are very slowly adjusting to an extended loading event that ended a week ago. Some slopes are stable, others are not, and it is difficult if not impossible to differentiate between the two. Patience is key with a persistent slab avalanche problem. The consequences of triggering one of these large slab avalanches are likely to be severe.

Avalanche Discussion

Moisture is to move into the area tonight. Snowfall rates of one to three inches per 12 hour period are expected overnight and through the day on Tuesday. This snowfall is to favor the Teton Range. Morning temperatures are to be near twenty degrees at all elevations with highs in the upper twenties at 9000 feet and warmer below. Winds are to be from southwest with five to fifteen mile per hour averages. The general avalanche hazard will be Moderate above 8000 feet. In areas underlain by weak faceted snow, as described above, skiers or riders could trigger slab avalanches to the ground. Although these slabs have become less sensitive, a single person can still cause a large avalanche, even in terrain that has been previously tracked. In this scenario, where a persistent weak layer underlies harder, settled snow, tracked slopes fail when either the load is increased (such as multiple people at once) or when a particularly weak or thin spot on a slope is impacted. Although only danger level 2, Moderate hazard with a well distributed persistent weak layer is not a go sign to get into steep avalanche terrain. Evaluate snow and terrain carefully to identify where the weak layer is present. Avalanches below 8000 feet are not expected.

Regions covered