Photo: Great Sand Dunes National Park

The park contains the tallest sand dunes in North America, rising about 750 feet from the floor of the San Luis Valley on the western base of the Sangre de Cristo Range. One of the most unusual features of the park happens at Medano Creek, which borders the east side of the dunes and is located next to the Visitor Center and Bookstore. Because fresh sand continually falls in the creek, Medano Creek never finds a permanent and stable streambed. Small underwater sand dunes that act like dams continually form, and break down. So waders in the stream see surge, which look like waves of water flowing downstream at intervals of just a few seconds to a minute or more. In a high-water year, these surges can be as much as a foot in height, resembling ocean waves. When I was there in July this water shown in the picture was absolutely freezing cold. Its nice to finally get across it and bury your feet in the hot sand. Also when attempting to walk up to the highest peak of the sand dunes bring appropriate gear, including water!