It is an American system used internationally to rate the difficulty of navigating a stretch of river or a single rapid. The scale ranges from Class I (easiest) to Class VI (extremely dangerous / unraftable). It takes into account wave height, water speed, technical manoeuvres required, and consequences of a mistake.

While possible with a professional guide on a commercial rafting trip, solo beginners should avoid Class III until they have mastered basic paddling techniques and self-rescue skills. Class III features moderate, irregular waves and strong currents that can flip small craft. Always go with experienced companions.

Class VI rapids are considered extremely dangerous and are typically not run, even by experts. They involve unpredictable, life-threatening hazards where a mistake almost certainly results in serious injury or death. Many Class VI rapids have only been attempted a handful of times in history, if at all.

Yes, scouting is highly recommended for Class IV rapids. Intense, powerful water and complex manoeuvres often hide dangers such as undercut rocks or hydraulics. Even experienced paddlers walk the riverbank to plan their route. Never rely solely on previous knowledge—water levels change daily.

Higher classes demand specialized equipment: throw bags, helmets, and reinforced rafts become mandatory from Class III onwards. For Class V, full-face helmets, rescue PFDs, and sometimes dry suits are used. Always match your gear to the maximum expected difficulty, not the average.

Absolutely. River difficulty varies with water level, seasonal flow, and even after floods or landslides. A Class II at low water may become Class IV in high spring runoff. Always check current conditions and local guides before setting out.