Most river classification systems are scaled on the class I to class VI scale. In this case, a class I is easy, a class VI is unrunnable, and class V is the limit of commercial and sane rafting. Below is a copy of the International Scale of River difficulty chart. A plus sign (+) after the rating indicates there may be a number of rapids with difficulty slightly higher than the indicated level, but not as difficult as the next.
Previous Rafting Experience: As a general rule, when participating in a professionally guided trip with the proper equipment, first-time and veteran rafters alike thrive on class III, III-IV, and even most class IV whitewater; such as the White Salmon. On the other hand, rafting class IV+ and V whitewater such as the Wind and Middle Owyhee requires previous rafting experience. Especially the Wind, we usually require that people have been rafting with us on at least two different river trips before we allow participation on this river!
River Flows: The level of a river can drastically change the character and difficulty with fluctuation in water levels. Inquire with are office about the latest river flows (especially in the spring). If a trip cannot be run with a reasonable assurance of success, we will, with as much advanced notice as possible, allow trip members to choose an alternative river on the same date, or the same river at a different date.
Class I–Easy
Waves small, passages clear; no serious obstacles.
Class II–Medium
Rapids of moderate difficulty with clear passages.
Class III–Difficult
Waves numerous, high, irregular; rocks; eddies; rapids with passages clear though narrow, requiring expertise in maneuvering. Rivers of Class III and III+ that River Drifters runs commercially include:
Class IV–Very Difficult
Long rapids; waves powerful, irregular; dangerous rocks; boiling eddies; powerful and precise maneuvering required. Rivers include:
Class V–Extremely Difficult
Exceedingly difficult, long, and violent rapids, followed by each other almost without interruption; riverbed extremely obstructed; big drops; violent currents; very steep gradient. Paddlers must pass our prerequisites and have prior class IV rafting experience or better, preferably with River Drifters. Rivers include:
Class VI–Unrunnable
Just like it says- Don’t even think about it, no matter what your life insurance policy is!