Whitewater Classifications

Thinking of running a river in your canoe or kayak? It's smart to know what you're getting into before you go. The water classification system explained here is used around the world to describe the level of difficulty for paddlers.

Keep in mind that a variety of other factors, such as the amount of recent rainfall or snowmelt, can affect the classification of a river or set of rapids. Weather, water temperature and remoteness can pose additional risks to paddlers, increasing the difficulty of running a river.

Class I: Easy

The easiest class features fast-moving water that has riffles and small waves. What obstructions exist are obvious and easily missed, even by novices. Risk to swimmers is slight and self-rescue is easy.

Class II: Novice

This water features straightforward rapids with wide, clear channels. Occasional maneuvering may be required, but trained paddlers can easily avoid rocks and medium-size waves. Scouting is typically not necessary. Injuries to swimmers are rare, and group assistance, while helpful, is seldom needed.

Class III: Intermediate

Class III water has rapids with moderate, irregular waves that may be difficult to avoid and can swamp open canoes. Boaters may need to perform complex maneuvers in fast current and have good boat control for tight passages and strong eddies, particularly on large-volume rivers.

Large waves or "strainers" (partially submerged tree branches or other debris than can strain a paddler out of the boat) may be present but can usually be easily avoided. Scouting is advisable for inexperienced parties. Injuries to swimmers are rare. Self-rescue is usually easy, but group assistance may be required to avoid long swims.

Class IV: Advanced

This is turbulent water with intense, powerful yet predictable rapids. Depending on the character of the river, a paddler may face unavoidable waves and holes or constricted passages. A confident, reliable eddy turn may be needed to initiate maneuvers, scout rapids or rest.

Rapids may require immediate responses and sure moves to avoid dangerous hazards. Scouting is necessary the first time down. Risk of injury to swimmers is moderate to high, and self-rescue may be difficult. Group assistance for rescue is often essential and requires practiced skills. Kayakers should be able to perform a reliable Eskimo roll.

Class V: Expert

This class features extremely long, obstructed or violent rapids that expose a paddler to above-average danger. Drops may contain large, unavoidable waves and holes or steep, congested chutes with complex, demanding routes. Rapids may continue for long distances between pools, demanding a high level of fitness and stamina. Eddies, if any, may be small, turbulent, or difficult to reach.

At the extreme end of Class V, several of these factors may be combined. Scouting is mandatory but often difficult. Swims are dangerous, and rescue is difficult, even for experts. A very reliable Eskimo roll, proper equipment, extensive experience and practiced rescue skills are essential for survival.

Class VI: Extreme

These runs often represent extremes of difficulty, unpredictability and danger. The consequences of errors are very severe and rescue may be impossible. This classification is for teams of experts only, at favorable water levels, after close personal inspection and taking all precautions. This class does not represent water that is considered impossible to run.