360° panorama by John Austin Roberts.
Click the image to open the interactive version.

The High Dune is the highest dune above sea level within the Great Sand Dunes National Park, rising 650 feet above the valley floor to an elevation of 8,691 feet.  The dunes of the park are the highest and tallest in North America.  The nearby Star Dune rises 750, but starting at a lower elevation in the valley, reaches only 8,617 feet above sea level - still, a very tall dune when seen from its base or while attempting to hike it!The dune field covers 30 square miles and reaches depths of 300 feet below the valley floor.  More sand around the edges is covered by plants and seasonal marshlands formed by the streams coming down from snowmelt in the Sangre de Christo mountains.  The prevailing winds and streams work to keep the dunes from blowing out of the valley.  The streams run around the borders of the dunes, capture blowing sand returning it to the valley where the winds pick it up and bring it back to the dunes in a cycle that has gone on for a long time.