The sand of the ancient lakebed was exposed when the mountains were thrust up by a tectonic plate shift. The sand blew up into dunes against the The Sangre de Cristo Mountain Range in South-Central Colorado. The Medano Creek bed usually dries out by August, but because of the enormous snowfall last winter, the creek still flows albeit a few inches deep. The summer temperature of the sand can exceed 150 degrees, so we walked in the creek bed, cooled by the ice melt. Some of the dunes are 750 feet high and range for 30 square miles. The grazing land of the San Luis Valley bumps up against the dunes that are nestled into the mountains, providing a great variety of ecosystems. Their beauty inspired many photos. If you look closely, you will see people climbing the dunes.
