What are the levels of waves in white water rafting?

White water rafting typically categorizes river rapids into six levels, ranging from Class I to Class VI. Class I represents easy, moving water with small waves, while Class VI denotes extremely dangerous rapids that are often considered unrunnable. Class II features straightforward rapids with occasional obstacles, Class III has more difficult rapids with moderate waves, and Class IV offers intense rapids that require precise maneuvering. Class V rapids involve very difficult conditions with high risk, demanding expert skills and experience.