International scale of river difficulty

[1] The scale was created by the American Whitewater Association to evaluate rivers throughout the world, hence international in the title.

[3][4] The grade reflects the technical difficulty and skill level required associated with the section of river.

Often a river or rapid will be given a numerical grade, and then a plus (+) or minus (-) to indicate if it is in the higher or lower end of the difficulty level.

Classifications can vary enormously, depending on the skill level and experience of the paddlers who rated the river.

Some rivers with high volumes of fast moving water may require little maneuvering, but will pose serious risk of injury or death in the event of a capsize.