AVALANCHES CAN ONLY OCCUR ON SLOPES STEEPER THAN ABOUT 25 DEGREES AND THEY MOST OFTEN OCCUR ON SLOPES BETWEEN ABOUT 35 AND 45 DEGREES.

Learning to recognize avalanche terrain is the first step in the avalanche hazard evaluation process.

31 °slope

      The steepness of a slope, its aspect (which direction it faces), the slopes shape and its natural features are all important in determining whether a slope can slide. Of all of these, the steepness, or slope angle, is the most important.

      Most slab avalanches occur on slopes with starting zone angles between about 30 and 45 degrees, but slabs occasionally occur on slopes less than 30 degrees.

      Slopes steeper than about 50 to 60 degrees tend to sluff snow constantly, and slopes about 25 degrees or less are generally not steep enough. Snowmobiling and highmarking are fun on slopes in the 30-40 degree range, thus we have our dilemma. We like to go where the slab avalanches most often occur.

      And you don't even have to be snowmobiling on a slope for it to avalanche. This is a very important concept. All of the snow is connected. You can be traveling on a flat slope or snow covered road and if the snowpack is unstable enough, even though you are not on a steep slope, you can trigger a slide on a steeper slope above you. Remember, all of the snow is connected. It is critical to know what is above you as you travel.

      The better you are at determining slope angle and recognizing hazardous terrain, the better choices you can make when traveling in avalanche country.