Avalanche forecast

Snake River Range

Bridger-Teton Avalanche Center
View on map

Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche danger is Moderate but could rise by late this evening at upper elevations. The danger is highest on steep northerly slopes where slabs 1-3 feet exist. Up to 10 inches of new snow by tonight and moderate westerly winds will raise the danger on steep slopes loaded by the wind. Evaluate steep, wind-drifted slopes carefully where you will most likely trigger an avalanche.

Avalanche problems

  • Wind Slabs

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

    The incoming storm will bring 6-8 inches of new snow at upper elevations by tonight, combined with moderate westerly winds. This will build slabs on lee aspects sitting on a variety of weak surfaces, including recent rimed snow, sun crusts, and old wind slabs from earlier in the week. These surfaces have been observed up to 10k on all aspects and will create slick surfaces for new snow to slide on.  Small slabs will trigger easily (touchy) by this evening in steep terrain. Look for signs of this problem in areas exposed to the wind at middle and upper elevations. Shooting cracks, dense pillows, and collapsing may all be present by this evening.

  • Persistent Slabs

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

    The likelihood of triggering slabs 1-3 feet thick has decreased, and in the last week, only one avalanche was reported that failed at the mid-December interface. The snowpack has gained strength this week, aided by warm temperatures, but weaker snow still exists in the bottom half. This problem is most pronounced on shady west through north through east aspects at middle and upper elevations. Some snowpits continue to show propagation in extended column tests, indicating that the problem has not completely gone away. With the incoming storm and up to 4 inches of snow water equivalent(SWE) forecasted by Monday, avalanches may fail at the mid-December interface.

    (12/21/2024)

    A large natural hard slab avalanche in the Snake that occured somtime around 12/18.

Avalanche Discussion

A very large storm is on the doorstep, with almost 5 inches of SWE forecasted to arrive by early next week. A few things currently on my mind;

  • I don’t expect the avalanche danger to rise significantly until later tonight, based on the forecast. That said, monitor new snow depths as you travel and consider where wind is moving this snow.
  • Keep an eye out for new snow instabilities late in the day. Small wind slabs and sloughing will occur by tonight on steep slopes. This problem will be worse in wind affected areas. 
  • There are several weak and slippery surfaces for new snow to slide on - hand pits and stomping on small test slopes will give great information as things change throughout the day
  • A little new snow will help cover rocks and logs at lower elevations, but until snow really stacks up, keep this hazard in mind.

This will be an exciting storm with a lot of snow and wind. Please continue to send in observations this weekend and let us know what you see!

Regions covered