International Scale of River Difficulty
Class I- Easy  Few or no obstructions; fast moving water with riffles; risk to swimmers is slight.

Class II- Novice  Wide clear channels; occasional maneuvering; rocks and medium-sized waves are easily missed by trained paddlers; swimmers are seldom injured; assistance is helpful but rarely needed.

Class III- Intermediate  Rapids with moderate, irregular waves which may be difficult to avoid and capable of swamping a boat; complex maneuvers in fast current and narrow passages require good boat control; large waves, holes and strainers may be present but are easily avoided; powerful current; scouting advisable; swimmers are unlikely to be injured but assistance may be needed to avoid a long swim.

Class IV- Advanced  Intense, powerful rapids; turbulent water; may involve long, unavoidable wave trains, holes or constricted passages demanding fast maneuvers under pressure; may require “must” moves above dangerous hazards; risk of injury to swimmers is moderate to high; group assistance to swimmers requires practiced skills.

Class V- Expert  Long, obstructed, turbulent rapids; drops may contain very large unavoidable waves, holes or steep congested chutes with complex demanding routes; several of these factors may be combined at the upper level of this class; rescue is extremely difficult; above average rescue skills are essential. Risk of injury is real.

Class VI- Almost Impossible  Difficulties of Class V are carried to the limits of navigability; very dangerous; risks are high and rescue may be impossible; for teams of experts only under favorable conditions. Risk of injury is high.

Many rafters cannot swim but you should be comfortable in water. On all trips, Coast Guard-approved PFDs are provided and must be worn. On advanced trips it is recommended that you have basic swimming skills. In general you should be comfortable in water and all rafters should be able to follow directions.