Welcome to Great Sand Dunes Oasis
On the eastern side of the remote, high-mountain San Luis Valley, between the Blanca Massif and Crestone Needle, are the Great Sand Dunes, the tallest sand dunes in North America. The dunes cover approximately 39 square miles and rise to almost 750' above the valley floor. The dunes are the product of the wind and rain eroding the San Juan and Sangre de Cristo Mountains that ring the San Luis Valley. They have collected here because the prevailing winds across the valley blow in this direction. But here, at the foot of the mountians, the wind has to drop some of its load of sand in order to clear the mountains. So over the course of millenia, the dunes have built up to where they are today. And tomorrow they will be different because the wind still blows and still moves and deposits more sand here.