Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Human triggered avalanches remain possible at ALL ELEVATIONS today and they are LIKLEY at the middle and upper elevations within the Wyoming Range. Lingering wind slabs are the primary concern in the alpine. On southerly aspects recent storm slabs and persistent slabs could activate with solar input today. Of particular concern are steep, unsupported slopes on the southern half of the compass that are in and around large cliff bands. Monitor the effects of the sun on the snow surface, and pay attention to signs of instability within wind affected snow such as cracking. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Lingering beneath a hard slab lies weak layers buried 2-3’. The Feb 18th layer is our main concern due to an increase in avalanches in the Wyoming Range(Shepard Creek, Hoback Peak). The Greys zone has a diverse snowpack nestled between each individual mountain range. The Salt and Snake River Ranges have not seen the uptick in recent avalanche activity or propagating results in stability tests. Our main focus is on the heightened avalanche danger in the Wyoming Range. Increased loading from this recent storm will add stress to these weak layers, especially in wind loaded terrain. Reported avalanches have been triggered remotely, and this potential will remain today. Avoid slopes over 30° and understand that large avalanches can be triggered remotely from gentler slopes above, below, or beside steep slopes.

    (3/7/2023)

    This avalanche was triggered remotely by the skiers on the rib well to the right of the start zone.

    Photo: Dan Janjigian

  • Wind Slabs

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

    Lingering wind slabs that are 1-2 feet deep exist on many aspects at the middle and upper elevations. These slabs are primarily 4F to 1F in hardness and rest on top of fist-hard decomposing snow from the powder cycle prior to the storm. Cold temperatures in the wake of the atmospheric river have preserved this instability, with relatively little settelment occuring within the new snow overnight. Strong winds on Friday have deposited snow below traditional start zones, especially in and around major cliff bands. Solar input should increase the reactivity of these hard slabs today.

    Loose snow avalanches (both dry and loose) could become a problem with the solar input today. Many cornices are reaching their zenith for the season. Be aware that these large cornices often break further back than anticipated and can trigger unusually large avalanches for the given conditions. 

Avalanche Discussion

No new snow to report for the Greys River Zone this morning. Temperatures currently range from single digits to the mid teens  in the valleys and are in the single digits on the peaks. 

The recent atmospheric river event left up to 1.2 inches of water at the upper elevations of the Greys in a 72 hr window. Very strong and sustained SSW winds hammered the upper elevations. Rain line reached the the 6700' elevation level, primarily on the west side of the various ranges. Western Wyoming is under a short wave ridging pattern with snow showers returning later this evening. 

Recent avalanche activity has involved wind slabs and persistent slabs that were size 1-2, including some avalanches that were remotely triggered from afar. 

From forecaster Drinkard:

Our focus shifts to the persistent slab problem found in the Wyoming Range. This area has experienced numerous large avalanches on the Feb 18th weak layer. Rapid loading of snow 2 days ago will stress this layer. Other areas are not as dangerous, as the Feb 18th layer is trending towards dormant in the Snake and Salt River Ranges. Unfortunately, we don’t want to count our cards quite yet and neglect the possibility of a persistent slab avalanche. Use careful judgment if recreating in the Wyoming Range as the combination of wind slabs with a persistent slab is a deadly combo. 

 

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