Photography in the Great Sand Dunes National Park can be a year round event. Spring brings wildflowers along with thousands of cranes and other waterfowl to the area. Summer brings wonderful warm weather for nighttime photography, with a sky full of stars making it particularly attractive. In Fall, the dunes are surrounded with color from aspen trees and in Winter the dunes take on a surreal look if there is snow on the sand.
The Park contains the tallest sand dunes in North America, rising about 750 feet (230 m) from the floor of the San Luis Valley on the western base of the Sangre de Cristo Range, covering about 19,000 acres (77 km²). They are perhaps 12,000 years old.
There are several streams flowing on the perimeter of the dunes. The streams erode the edge of the dune field, and sand is carried downstream. The water disappears into the ground, depositing sand on the surface. Winds pick up the deposits of sand, and blow them up onto the dune field once again.
Digging a few inches into the dunes even at their peaks reveals wet sand. If the streams were to dry up, the dunes would disappear; in fact part of the motivation of turning the Monument into a National Park was the extra protection of the water, which Colorado’s cities and agriculture covet.
The park also contains alpine lakes and tundra, six peaks over 13,000 feet (3,940 m) in elevation, ancient spruce and pine forests, large stands of aspen and cottonwood, grasslands, and wetlands — all habitat for diverse wildlife and plant species.
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 surges—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. Building sand castles with the creek sand is a popular visitor activity.
Getting to the dunes requires walking across the wide and shallow Medano Creek, which flows only from spring to early summer. Hiking is permitted, with the warning that the sand can get hot in the summer, up to 140° Fahrenheit (60° Celsius). The area gets snow in the winter.