Note the nearly white sandstone in this area, in contrast to the deep red sandstone near the visitor center. The red color in the rock is caused by traces of iron minerals that have oxidized, or literally rusted. Subtle changes in the colors, from white to tan, purple, maroon and red are thought to be caused by underground water movement which leached the oxidized iron. Many believe that wind erodes desert landscapes such as this one. However, wind plays a minor part, mainly moving loose sand and heaping it into small sand dunes.
Water is actually responsible for most of the landforms within the park.
That seems fantastic in this arid landscape, especially if one has only seen the rare and gentle winter rains. But every few years the area is subjected to heavy rains from strong summer thunderstorms, and even more rarely, prolonged winter rain like the two-week rain of January 1993. The power of water becomes more apparent when one multiplies the effects of one of these storms by millions of storms occurring over many millions of years. .