Avalanche forecast

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
View on map

Avalanche danger

Sat
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
Open full map
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Heavy snowfall rates in combination with strong, intense wind and rising temperature will create reactive storm/wind slabs and increase avalanche danger significantly throughout the day. These conditions will stress buried weak layers with the potential to trigger a much larger avalanche remotely from gentler terrain above, below or beside steep slopes (as seen recently in the Wyoming Range). Due to the high consequential and unpredictable nature of these avalanches, avoid avalanche terrain by the afternoon and think very conservatively today. 

Avalanche danger will increase to High by the late afternoon with over 1” of snow water equivalent forecasted by the end of the day. This will pertain to areas with a weak, shallow snowpack such as the Wyoming Range.

Avalanche problems

  • Wind Slabs

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

    Strong S/SW winds with forecasted highs of 30-40 mph with gusts to 60 mph combined with large amounts of new snow will form sensitive wind slabs.  Winds will shift to the W by the afternoon with the frontal passage. These slabs will be most sensitive today during peak snowfall and wind in the afternoon. Slab depths 2-3’ deep will be possible. Dense snow due to warm temperatures will create hard slabs in the upper and middle elevations. Avoid wind loaded terrain and look for obvious signs of instability such as cracking, drifts, and stiffened surfaces.

  • Storm Slabs

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

    Snowfall rates of 1-2”/hour with 16” of new snow by the evening will create widespread unstable snow. Slab depths will increase throughout the day. In addition, temperatures will increase creating upside conditions that are ideal for causing reactive storm slabs that are fairly uncommon in the Greys, especially this winter. This snow is falling on low density snow on northerly aspects, creating even more upside conditions. Southerly aspects harbor a recent melt freeze crust below some recent snow that will also be reactive.

    Wet Loose avalanches in the lower to middle elevations could be found today due to rain and rising snow levels rising potentially rise to 7500’-8000''.

  • 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, Deer Creek, Little Greys River). 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. Rapid loading during this storm will continually stress these weak layers. Reported avalanches have been triggered remotely, and this potential will increase today. Increased loading of over 1” of snow water equivalent will put a serious test to the layer during this storm. Freezing levels up to 8500’ could produce rain, increasing the chance of persistent slabs in lower to middle elevations. 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

Avalanche Discussion

Strong and Heavy

Here comes the atmospheric river. Today will be an interesting day in the mountains as vigorous weather conditions ramp up throughout the day. The combination of intense snowfall rates, radical winds and rising temperatures will create plenty of new snow instability. Avalanche danger will increase throughout the day, so it will be vital to constantly monitor for changing conditions and navigate through terrain accordingly. Remember, this forecast is just your first data point. It is your responsibility to verify the forecast and make your own decisions. Days like this can be difficult with the unpredictable nature of weather’s influence on a constantly evolving snowpack.

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 new snow will severely stress this layer. Avalanche danger will increase to HIGH by the afternooon if foreacsted snowfall comes to fruition. Avoid avalanche terrain if you are recreating in this area. Watch terrain above you and avoid large avalanche paths. Other areas are not expected to have this increased danger, 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 and neglect the possibility during rapid loading of this storm. Think very conservatively in the mountains today. Snow and rapid change do not get along with each other. 

Regions covered