The ice-free corridor route proposes that as the Last Glacial Maximum ended and the ice sheets began to retreat, a corridor opened between the eastern Laurentide Ice Sheet and the western Cordilleran Ice Sheet, running roughly north-south through what is now Alberta and British Columbia.

This corridor, when it was open, would have provided a passage from Beringia to the unglaciated interior of North America.

The timing of the corridor’s opening, and whether it was ecologically viable — whether it was able to support the plants and animals that a human population would need to travel through it — has been the subject of extensive research.

The evidence for the ice-free corridor’s ecological viability suggests that it was not open and functional as a route for human dispersal until roughly 14,000 to 15,000 years ago, and possibly somewhat later.

Before that time, even if the physical space between the ice sheets existed, it may have lacked the plant communities and prey animals that would have allowed a hunting population to survive while traveling through it.