The Avalanche Terrain Exposure Scale (ATES) is a system used to assess the potential danger of avalanches in a given area. The ATES system takes into account the terrain characteristics of a specific location, as well as the snowpack and weather conditions.
The ATES system is based on three factors: slope angle, terrain complexity, and exposure to overhead hazard. Each of these factors is assigned a rating on a scale of 1 to 3, with 3 being the highest rating and indicating the greatest potential for avalanche danger.
Slope angle is the first factor considered in the ATES system. The steeper the slope, the greater the potential for avalanches. Slope angle is classified as low (less than 25 degrees), moderate (25 to 35 degrees), or high (greater than 35 degrees).
Terrain complexity is the second factor considered in the ATES system. The more complex the terrain, the greater the potential for avalanches. Terrain complexity is classified as simple, moderately complex, or complex.
Exposure to overhead hazard is the third factor considered in the ATES system. This refers to the potential for avalanches to start above the area being evaluated and affect the area below. Exposure to overhead hazard is classified as simple, moderate, or extreme.
Once these three factors have been assessed, they are combined to give an overall rating for the area. The ratings range from 1 to 3, with 3 being the highest risk and indicating the greatest potential for avalanche danger.
The ATES system is an important tool for backcountry travelers, avalanche forecasters, and other professionals involved in avalanche safety. It can help people make informed decisions about where and when to travel in avalanche terrain, and what precautions to take to avoid avalanche danger.