Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
No rating
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Highlights

It will be easy to trigger avalanches on steep wind loaded slopes today.  New snow and increasing winds over the past 48 hours have created unstable conditions.  Triggering and getting caught in an avalanche could have serious consequences today, as obstacles lurk just below the surface.

Avalanche problems

  • Wind Slabs

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

    Snow totals over the last 3 days range from 10” to 24”.  Winds at the beginning of this storm cycle were light, but picked up significantly over the last 24 hours.  Additional snow and wind will make triggering more likely in the afternoon.  Expect to encounter wind slabs 1 to 3 feet thick in leeward terrain. It will also be possible to trigger storm slabs that were not affected by the wind and are sitting on a variety of weak layers.  These slabs will be sensitive to the weight of a single person.   Watch for obvious signs of unstable snow such as cracking and collapsing. Getting caught and carried in an avalanche today could result in getting dragged along bare ground and rocks. Approach terrain with a high level of suspicion and give yourself a wide margin for error.

  • Persistent Slabs

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

    Weak layers deeper in the snowpack pose a threat today as well.  While the interfaces between the new snow and old snow are varied, deeper layers are more consistent on upper elevation sheltered slopes.  Examples of this setup are highlighted in observations from the field over the last several days. This problem relates directly to the wind/storm slab problem, in that an avalanche triggered on the surface holds the potential to step down into these deeper weak layers. Slab thickness will be in the 2-3 foot range. Avoidance is the best bet for the time being.  Giving these deeper weak layers time to adjust to the overlying load will be critical in staying out of trouble.

Avalanche Discussion

Snowfall has been below average over the last 2 months.  This has resulted in a weak and shallow snowpack across the Tetons.  Sheltered mid and upper elevation terrain is harboring the weakest snow.  Facets and surface hoar were prevalent on the surface prior to this most recent loading event. Digging further down into the snowpack, observers have noted weak snow at varying depths.

New snow and wind have combined to add significant stress to the underlying snowpack.  The good news is that in the lower elevations and on solar aspects the new snow has fallen on bare ground.  Elsewhere, it can be assumed that the interfaces between the old and new snow are suspect at best.  As improving coverage allows for travel into more terrain, approach with caution.  Giving this new snow time to bond will require patience and a conservative approach.

Regions covered