An avalanche can be a truly terrifying disaster. Avalanches occur when  the load of snow on a slope becomes too great and through the force of  gravity the snow moves downhill. Depending upon the size and speed of  the avalanche, these can be deadly natural events.

Risk Factors

There are some conditions that can make avalanches more likely, including:

  • History of avalanches: If there have been avalanches in the area before, this is a very good indication that there will be another one.
  • Slope angle: Most avalanches occur on 30 to 45 degree slopes, but depending on the condition of the snow pack can occur at any angle.
  • Weather: Recent significant snowfall greatly increases the chance of an avalanche. When new snow doesn't have an opportunity to bond to previous layers, this can set up slab avalanches. Snowfall amounts of a foot or more in a 24 hour period would be considered significant.

There are many other factors that can increase the chances of an avalanche. Check the National Snow and Ice Data Center (NSIDC) for more information.

An avalanche going down a mountain.


Most importantly there is the  potential loss of life or risk of serious injury associated with  avalanches. Secondary to that, impacts include:

  • Impeded  travel: Avalanches can shut down major highways into and out of Teton  County such as Highway 22 (Teton Pass), South Highway 89 (Rafter J area,  Snake River Canyon), and Highway 191 (Hoback Canyon). Check Wyoming  Department of Transportation's road condition page to see if your travel  routes are closed due to avalanches or avalanche control.
  • Economic  losses: If employees are unable to come into work due to highways being  shut down, businesses will not be able to operate at capacity.  Additionally, closed roads will prevent people from coming to Teton  County to recreate and vacation.
  • Increased strain on emergency  services: Increased amounts of people in the back country means more  search and rescue call outs. With the time and effort required for each  rescue, simultaneous requests for help can be a significant strain on  local resources. If roadways are closed due to avalanches, this not only  makes it difficult or impossible for emergency services such as law  enforcement or EMS to respond to affected areas, but will also make it  difficult for responders to report for their shifts.