a

I - Easy

Small waves, clear passages

II - Medium

Clear passages, irregular waves

III - Difficult

Numerous waves, rocks, eddies and narrow passages

IV - Very Difficult

Powerful waves, numerous rocks, difficult passages, precise maneuvering required

V - Extremely Difficult

Long and violent rapids in quick succession, violent currents, steep gradients

VI - Unrunnable

Not attempted by commercial outfitters