Avalanche forecast

Tetons

Bridger-Teton Avalanche Center
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Avalanche danger

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

Heavy snowfall rates in combination with strong, intense wind and rising temperature will create widespread reactive storm/wind slabs. Look out for actively wind loaded terrain where sensitive wind slabs will be found. Think conservatively today as this rapid loading of dense snow with intense wind will increase danger throughout the day making human triggered avalanches likely.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    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’ 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.

     

     

     

    (3/5/2023)

    Skier-triggered avalanche on Pucker Face; despite spring-like weather, things are not open season yet, particularly in steep and rocky upper-elevation features that will see ever-increasing sunshine.

  • 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 Tetons, 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 up to 8000’.

  • Persistent Slabs

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

    Lingering beneath a hard slab lies weak layers buried 2-3’. The Feb 18th layer is our main concern. Recent avalanche activity on this layer has been scarce, but propagating results in stability tests keeps us on edge still. This layer is composed of a facet, crust combination found on solar aspects in the middle and upper elevations. Lower elevations contain this same combination, as well as weak, faceted snow on all elevations. Increased loading of 1” of snow water equivalent will put a serious test to the layer during this storm. Snow levels rising to 7500'-8000’ could produce rain, increasing the chance of persistent slabs in lower to middle elevations.

    (3/7/2023)

    This avalanche may have failed naturally though an animal trigger seems possible as well. 

    Photo: Brad Boner/JH News and Guide

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. The Feb 18th layer and persistent slab is trending dormant, but we don’t want to count our cards quite yet during rapid loading of this storm. Low elevations have seen an uptick in activity impacting roads (Spring Gulch, HWY 89) . Increasing snow levels will form rain which could create large persistent slab avalanches in these lowest elevations. Think conservatively in the mountains today. Snow and rapid change do not get along with each other. 

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