White Canyon, Utah. A canyoneer pulls her rope after rappelling into a pool in the White Canyon complex of southern Utah. White Canyon and its tributaries have cut deeply into the Cedar Mesa Sandstone formation just upstream of Glen Canyon and the Colorado River. Since this entire region was pushed upwards by colossal geologic forces beginning about 10 million years ago, the sandstone layer-cake of the Colorado Plateau has been incised with countless deep, narrow canyons. Even during the blazing heat of summer, deep cold pools of water necessitate the use of wet suits when exploring these canyons.