Home / More 360 panos     Pictures of Grand Canyon National Park Cliff above Unkar Rapids, Grand Canyon National Park
  The Grand Canyon was formed by a combination of the uplifting of the Colorado Plateau, and the Colorado River cutting almost one mile through the plateau. In the course of its 277 miles (446km), the Colorado River drops 2000 feet. Rather than being gradual, the river profile is like a staircase. Most of the drops occur at about 160 rapids. The rapids are generally formed by debris and boulders transported during floods from the many side canyons. Those debris constrict the flow, increasing the water speed. Some of the Grand Canyon rapids reach class V, on the International Scale of River Difficulty I-VI, with VI meaning “unrunnable” – if a rapid is repeatdely run that was once thought to be class VI, it is typically reclassified as Class V. Unkar Rapids, considered moderate in difficulty, are remarkable for the setting, on a wide bend surrounded by undulationg badlands in the most open part of the Grand Canyon.