An international scale that rates individual rapids from class I (easy) to class VI (nearly impossible) is used in all our river descriptions. A rapid may vary in terms of time from just a few seconds to 20 seconds or more.

Class I
Gentle, moving water. Very small waves requiring little or no maneuvering.

Class II
Regular waves, easy to see, may reach 3 to 4 feet in height. Avoiding rocks, river bends or other obstacles may require simple maneuvering.

Class III
Large, continuous series or sets of waves, some in excess of 6 feet. "Holes" or "hydraulics" may be present, and can be run or avoided. Small drops, ledges or waterfalls may be present. Scouting the rapids is suggested for all but the most experienced of river persons.

Class IV
Confused and erratic waves or holes. Large obstructions need to be avoided in what are referred to as "must moves." Risk of injury if swimming without benefit of a raft! Very difficult and scouting is required.

Class V
For most people, class V goes off the "fun" scale and enters the "kinda scary" scale! Very challenging for even the most experienced river persons. High risk of capsize or injury. Limit of navigation and scouting is essential.

Class VI
Virtually non-navigable, or navigable only at particularly favorable river levels.