Avalanche forecast

Snake River Range

Bridger-Teton Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Watch for warming snow surfaces that may become wet and unstable in the sun. While small and limited to solar aspects, this type of avalanche can be a problem in big terrain.  A chance of triggering large slabs deeper in the snowpack also persists.  Follow safe travel practices, never put more than one person on or below a slope, and look for signs of wind affected snow on steep slopes where a deeper avalanche may be triggered.

Avalanche problems

  • Loose Wet

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

    A wet loose avalanche or cornice fall large enough to trigger an avalanche or entrain enough snow to bury a person would be surprising but not impossible.  Signs of unstable snow and potentially weakening cornices will be obvious. Early signs would include being able to make a snowball that wets your glove or loose surface snow rolling down surfaces around cliff bands. When this activity begins to build, move to shadier terrain. Think twice before traveling under steep, rocky slopes baking in sunshine. 

  • Persistent Slabs

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

    Signs of wind affect on ridges and cliff bands are clues that deeply buried weak layers may be close enough to the surface to be triggered.  These weak layers of snow that are buried 2-4 feet below the surface exist primarily on the north half of the compass. Although triggering an avalanche involving these layers has become less likely, it can still occur, especially above 8000 feet in terrain that is connected to very steep (greater than 35 degrees) slopes and have varying snow depths.  If triggered, these slabs are likely to release as large, hard slab avalanches. Snowpack evaluation and safe travel practices remain the best methods to avoid triggering an avalanche involving the old snow layers. 

     

    Large persistent slab avalanche that occurred just over a week ago  in the Snake River Range. The trigger in unknown but was likely a falling cornice. Thanks to High Mountain HEli for the photo and critical observation.

Avalanche Discussion

A warming snowpack is never a good thing for recreation unless the snowpack is already isothermal and refrozen which our current snowpack definitely  is not. Yesterday's temperatures rose higher under cleaer skies than expected which led to some wet, loose activity. Warmer temperatures are forecast but increasing winds today with the potential for clouds building brings some uncertainty to these heat induced problems. The good news is that the evidence for these problems is obvious. Our deeper persistent weak layer near the ground should be sheilded from any larger, natural triggers due to their location on shady slopes but keeping a careful eye on terrain above and the timing of warming conditions would be a good idea.

The weak layers buried in mid and late December are well preserved in the snowpack. Although the triggering of an avalanche involving this snow is becoming less likely, areas still exist where a person or a group of people could cause a slope to fail.  This could happen while on a previously tracked slope or even when adjacent to steep terrain. Be wary of terrain that is so steep that snow could now be enticing but you suspect it could be covering a shear rock face or small cliff band that was exposed just a month ago. Looking at the snow layering in a drainage is the best way to understand the extent of this weakness and do not trust that such an evaluation will be the same in relatively close areas as the magnitude of this problem can vary greatly from one drainage to the next. 

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