Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The possibility continues for human triggered avalanches to occur today in the Teton forecast area. Small wind loaded slabs could be triggered in high terrain along ridge crests and in cliff bands. Although less likely, a slight chance persists to trigger large and dangerous slabs involving old buried weak layers at the mid and high elevations. Avalanches at low elevations are unlikely today. Watching for freshly wind drifted snow and avoiding slopes that may contain areas where the snowpack is thin are the best ways to avoid these avalanche concerns.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Considerable amounts of low density snow lies at the upper elevations. This light snow and winds that have veered from the south to the northeast over the last several days. Since 4pm, winds have averaged near 20 miles per hour from the northeast. Shallow, soft wind slabs with depts to eighteen inches lie in steep terrain near ridgecrests and peaks. Watch for areas of fresh wind loading, particularly near cliff edges or in transitions into couloirs or very steep terrain. 

    (1/23/2023)

    Varying wind directions over the last several days. 

  • Deep Persistent Slabs

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

    Weak snow buried in late November continues to pose a threat to backcountry users.  Although most steep terrain can be crossed without occurrence, the chance for a large and destructive avalanche continues. Very few avalanche events involving this layer have occurred since early December but two of them were serious and could have had fatal outcomes. This weak snow can be found on east through south to west facing terrain above 8000 feet. A weak spot, or thin spot on a slope needs to be impacted to trigger such a slide. Avoid terrain that could have a shallow area such a recently buried cliff band now that we are in a relatively deep mid-season snowpack. Avoid skiing terrain as a group or grouping up mid-slope as large triggers also increase the chance of triggering a deep slab. If triggered these slabs will be hard and have depths to five feet. 

    (1/16/2023) Slide initiated on skiers far upper left side of crown in shallower snow and propagated into deeper snow.

Avalanche Discussion

The biggest problem with both avalanche problems right now is most terrain can be hit and with low likelihood of triggering a slide. However, whether a tiny slide carries someone over consequential terrain or if someone were to trigger a large, deep slab the consequences are likely to be severe.  Awareness of surface loading and avoiding extreme terrain is the way to avoid the wind slab problem. A more thoughtful approach is needed to avoid the deep slab problem. Looking into the layering can identify the potential but avoiding terrain with features that may allow for thin spots, especially those in very steep terrain that is generally wind loaded during storm events is the safest approach to avoiding a large and destructive avalanche.  Note that the frequency of events involving this layer is extremely low. Since this layer was significantly buried, the two confirmed slides involving it were serious accidents. These were a month apart and occurred on December 16th and January 16th. There were only one or two other natural events that may have involved that layer reported in early January.  

The other thing to think about right now are snow surfaces. In a season with consistent snowfall, this has not been a focus for a while.  Near surface faceting is occurring in almost all terrain and noting where surface hoar is forming right now can help in terrain selection once future storms add new slab avalanche hazards. 

Regions covered