What do downhill skiing trails, rock climbing walls, and whitewater rivers have in common? If you said all three use a scale of difficulty to convey the skill level required to navigate them, you’re right on the money.
In the whitewater-paddling world, that classification system is the International Scale of Difficulty, developed by the North Carolina-based nonprofit American Whitewater. Recognized by river-runners from canoeists to kayakers to rafters, the scale ranges from Class 1 for beginners to Class 6 for the elite. The ratings aren’t exact, however. Subjective factors, such as the skill level of the rafter and the river conditions at the time it is paddled, can influence ratings.
When choosing a river to paddle, do your homework and scout potential hazards before leaving the shore. A river’s water level can change throughout the season or even during a single day, causing obstacles such as rocks or downed tree limbs—called strainers—to come into play. Choose a river within your comfort level before moving up in class for more of a challenge. Here’s how the classes break down:
Class 1 (Beginner): Moving water with no obstructions, and minimal waves and riffles. Swimming to shore and self-rescuing is easy.
Class 2 (Novice): Occasional maneuvering around obstacles is required. Waves up to 3 feet and rapids with wide, unobstructed channels are possible. Swimming and self-rescue require minimal training.
Class 3 (Intermediate): Fast current with multiple rocks and strainers, as well as waves over 3 feet, are likely. Paddlers should be able to perform tight, technical maneuvers and know how to navigate through narrow passages with submerged, yet easily avoidable, obstacles. Scouting is recommended. Risk of injury to swimmers is low to moderate. With the proper training, self-rescues are possible, though group assistance is useful.
Class 4 (Advanced): Fast, turbulent water with potential for unavoidable obstacles, namely large rapids, strainers, and holes. Scouting is often required. Paddlers must be able to perform tight, technical turns through tricky channels. Risk of injury to swimmers is moderate to high. Self- rescue is limited, based on conditions. Group assistance is highly recommended but might be difficult to initiate.
Class 5 (Expert): Long, torrential currents with unavoidable obstacles—namely violent rapids, deep holes, and narrow chutes—are typical. Some maneuvers must be executed with precision to avoid injury. Paddlers must have a high level of fitness, as few eddies provide opportunities for rest. Risk of injury to swimmers is high. Scouting is required but often difficult due to terrain. Group assistance is a challenge, even for those with proper gear and rescue experience.
Class 6 (Elite): Rivers of this class should be only attempted by teams of professionals with extensive technical ability, rescue skills, and experience.