The Bruneau Sand Dunes formed around 14,000 years ago when floodwaters from the Bonneville Flood carved a U-shaped basin in the middle of the Idaho desert, leaving huge sand dunes behind.
The Bruneau Sand Dunes formed around 14,000 years ago when floodwaters from the Bonneville Flood carved a U-shaped basin in the middle of the Idaho desert, leaving huge sand dunes behind.