Letter = Time and elevation gain

A = Not strenuous (1-4 hrs, 600m elevation gain, day pack)

B= Moderately strenuous (2-6 hrs, 600-1200m elevation gain, day or overnight pack)

C = Strenuous (4-10 hrs, 1000-2000m elevation gain, day or overnight pack)

D = Very strenuous and multiple days

Number = Terrain

1 = Gentle slopes, mainly trails

2= Moderate slopes, travel off trail

3 = Off track in mountainous terrain, may involve steep forest and/or roped glacier travel

4 = Difficult mountainous terrain. Advanced backcountry and climbing experience needed.

5 = Leader protection, hardware required

6 = Direct aid climbing