The specific plant communities that had characterized the glacial maximum were being replaced by the communities that now dominate the region.

The landscape was dynamic in ways that modern residents of Idaho might find barely recognizable.

Into this transitional landscape came the first human populations, moving along various pathways — coastal routes, interior corridors, perhaps multiple waves of migration.

The exact routes and timing remain debated.

What the archaeological evidence establishes is that by the terminal Pleistocene, people were present across much of western North America, using technologies that varied from the fluted Clovis points of the plains and eastern regions to the stemmed points of the Intermountain West.

The Western Stemmed Tradition itself is thought by many researchers to reflect the technological adaptation of people who were moving through and settling in the forested and riparian environments of the Pacific coast, the Columbia Plateau, and the Great Basin.