In this region of the Colorado River basin, the river is classified as an exotic stream. Exotic streams are those that originate in a humid region but flow through an arid region. The Colorado River begins in the high elevations of the Colorado Rockies of northern Colorado where the climate provides significantly more moisture. As the river passes Grand Junction, CO it enters a climate where the evaporation coefficient exceeds the precipitation coefficient, or desert. Here, the lack of precipitation means the river stream cuts downward much more rapidly than the regional wetness washes and mitigates the angularity of the landforms, forming canyons instead of gentle slopes. The constantly flowing stream cuts down while the lack of rainfall does not round off the sides of the stream bed.