Snake River Plain
Footprints of Collapsed Volcanoes
The Snake River Plain was formed by eruptions beginning in southwest Idaho 13 million years ago. As the North American continent shifted to the southwest over the stationary hotspot (now currently under Yellowstone), the earth’s crust melted into magma and erupted. To the southwest, a straight line of ancient volcanoes were formed. These volcanoes are oldest in the west and progressively younger to the east due to the continuous movement of the North American continent over the hotspot.
Big Southern Butte is one of the tallest volcanoes on the Snake River Plain.