A Guide to Understanding Rapid Classification

Curious How River Rapids are Classified?

Curious how the classification of rapids works? Wondering what the differences between Class I and Class V rapids are? We’re here to help you understand what to expect on a Whitewater Rafting or Scenic Float trip with Big Creek Expeditions.

Rapid classifications are not necessarily an exact science, however, most outfitters and recreational boaters tend to agree on the ratings of certain rapids. With that being said, the rapid classification system is only a guide and rapid classes can change significantly due to water levels or changes in the hydrology features over time.

Nationally recognized organizations like American Whitewater use the International Scale of River Difficulty, an Americanized version of a rating system used to rate rapid difficulty throughout the world.


Class I Rapids

You can expect fast-moving water with small waves and some ripples. The risk to swimmers is minimal and any obstructions should be obvious and should be easy to avoid.

Our Scenic Float trip features stretches of Class I water where you can take a swim, splash and sight-see.

On our Whitewater Rafting trip, you can expect to find Class I after the majority of our higher-ranked rapids--more commonly referred to as Drop-Pool in rafting jargon. In a Drop-Pool style river, rapids eventually mellow out, allowing you an opportunity to high-five your companions and celebrate successfully navigating a rapid before approaching the next rapid.

Class II Rapids

Experience level—Novice

These rapids feature wide channels that are clearly seen. Any obstacles are easily missed by trained paddlers, like rocks or strainers (trees). Expect medium sized waves that offer a good splash.

Enjoy some Class II Rapids on our Scenic Float trip, like the series of rapids named "The Ledges."

Class III Rapids

Experience level—Intermediate

These rapids can contain waves that are moderate in size and often irregular, requiring skilled boat control and some complex maneuvers. Larger waves may be unavoidable. According to American Whitewater, “Injuries while swimming are rare; self-rescue is usually easy but group assistance may be required to avoid long swims,” meaning that swimming is relatively safe in Class III rapids.

Whitewater Rafting on the Pigeon River in Tennessee is a mostly Class III experience at standard water flows, with rapid names like The Lost Guide, Full of Water, Powerhouse and Snap Dragon. There are also several Class IV rapids on the Upper Pigeon Whitewater Rafting section (see below).

Class IV Rapids

Experience level—Advanced

Class IV rapids are more difficult to navigate successfully, featuring powerful and turbulent water. Predictable, these rapids can have waves and holes that are hard to avoid, requiring a skilled guide to navigate a raft through often narrow or constricted passages. The risk of injury to swimmers is moderate, and poses a higher risk than swimming in a Class III rapid.

The Upper Section of the Pigeon River has a few Class IV rapids like Double Reactionary and Accelerator.

Class V Rapids

Experience level—Expert

Class V rapids require skills that are acquired by guides and recreational boaters over time. They pose an added risk to all paddlers, especially if you find yourself outside of your boat. Rescue can often be very difficult. Eddies/pools (remember Drop-Pool jargon) are few and far between, too difficult to reach or sometimes nonexistent, meaning that the opportunities to pause and take a break are, too. The rapids are often violent, highly constricted and feature multiple obstacles. Basically, we wouldn't recommend attempting these rapids without a solid skill set and adequately skilled and trained guides and boaters.

Class V rapids are often on a scale going from 5.1 to 5.9, where eventually they reach class VI. Class VI rapids are often exploratory and require teams of experts and highly trained professionals. The risk is severe. Oddly enough, once a Class VI rapid has been run sucessfully several times, it will bump down to an appropriate spot on the 5.1 to 5.9 scale

What Rapid Classes Mean to You

Leave it to the professionals if you intend to paddle rapids outside of your skill level. Water is a powerful force! Read the Safety Code of American Whitewater for more information


Amanda Clampitt