The original flooding of the reservoir had killed the vegetation and when the water level dropped, wind erosion removed layers of unprotected sand and silt, exposing trackways and bones of extinct mammals, as well as stone tools used by Paleoindian hunters.

[3] Eleven thousand years ago the Laurentide Ice Sheet had recently retreated from the area and the site was a windswept, semi-arid plain covered with grasses and low shrubby vegetation, similar to the mammoth steppes of Europe and Asia.

The rich open grassland and the reliable supply of water at the river supported herds of large, late Pleistocene mammals and other animals.

[4] Footprints and trackways preserved in silt include those of mammoths and the extinct camel Camelops hesternus, in addition to those of horse, bison and caribou.

[5][6] The herds of animals and the reliable supply of water attracted Paleoindian hunters, and the artifacts recovered from the site suggest that it was a hunting locality.