Obstructions are not life-threatening under normal circumstances. The route is clearly visible from the top of the rapid. Many of the New and Gauley's most entertaining rapids are Class III's. Class IV Very difficult water. Long, constricted, difficult passages that require complex maneuvering.
Conditions make rescue difficult.
Life-threatening obstructions, such as undercut rocks, may be present. Routes are often not readily apparently from the top of the rapid. Any Class IV rapid is serious business and requires the attention of everyone in theboat. Class V Extremely difficult and violent rapids with significant hazard to life in the event of a mishap. Rescue is very difficult and there is significant hazard to life.