Avalanche Terrain Exposure Scale

Video: Researcher Pascal Haegeli runs us through simple, challenging and complex terrain.

The Avalanche Terrain Exposure Scale (ATES) classifies routes and areas of terrain according to the severity of exposure to avalanche hazard.   It has three terrain classes: simple, challenging, and complex.

ATES ratings are available for many popular recreational areas in Canada. ATES rated terrain is displayed on the Online Trip Planner. ATES ratings are often available on signs posted at trailheads and on trail maps and guides.

ATES ratings are compiled by professionals who consider 11 weighted terrain parameters in ranking a trip or region:

  • Slope angle
  • Slope shape
  • Forest density
  • Terrain traps
  • Start zone density
  • Avalanche frequency
  • Runout zone characteristics
  • Interaction with avalanche paths
  • Route options
  • Exposure time
  • Glaciation

Photo: An example of ATES-rates terrain.