Summer light shines on Bruneau Dunes State Park

Bruneau Dunes State Park near Mountain Home, Idaho, is a unique topographical feature in a state renowned for its unique and wild character. This corner of southern Idaho desert is defined by basalt and rhyolite lava flows, sage brush, deep canyons and granite batholiths that have upheaved the earth into a small handful of alpine islands in an ocean of desert.

The park, purchased by the state of Idaho in 1967, is home to the tallest single-structured sand dune in North America. The dune rises to 470 feet above a small lake.

Among the Western Hemisphere’s sand dunes, Bruneau Dunes are unique in the way they’re formed: They’re the only dunes that form near the center of a basin. While other dunes, like North America’s tallest dunes at Great Sand Dunes National Monument in the San Luis Valley of Colorado, form at the edge of a basin by winds prevailing from a single direction, Bruneau Dunes were formed over the course of 12,000 years by varying winds. The wind blows from the southeast 28 percent of the time and from the northwest 32 percent of the time, keeping the dunes relatively stable. They don’t drift far.

Bruneau Dunes may have begun to form about 15,000 years ago when the Bonneville Flood–a torrent created when the Great Salt Lake overflowed its banks into what is now Idaho–inundated the area and deposited silt.

Photos © Greg Stahl