Known as the International Scale of River Difficulty, below are the six grades of difficulty in white water rafting. They range from simple to very dangerous and potential death or serious injuries.
Class 1: Very small rough areas, might require slight maneuvering. (Skill level: Very basic)
Class 2: Some rough water, maybe some rocks, might require some maneuvering. (Skill level: Basic paddling skill)
Class 3: Small waves, maybe a small drop, but no considerable danger. May require significant maneuvering. (Skill level: Some experience in rafting)
Class 4: Whitewater, medium waves, maybe rocks, maybe a considerable drop, sharp maneuvers may be needed. (Skill level: Exceptional rafting experience)
Class 5: Whitewater, large waves, large volume, possibility of large rocks and hazards, possibility of a large drop, requires precise maneuvering. (Skill level: Full mastery of rafting)