Colorado Whitewater Adventure
International Scale of River Difficulty
The rating of rivers is subjective. Rivers also change due to water levels, rocks that may shift on the riverbed, man-made influences, etc. On rivers rated on this website, ratings are based on medium water levels and should be used as a general guide. We have also used the minus or plus symbol to show that a river run may be a bit easier or harder than most runs of the same rating.