Perhaps the hunters who came through the ice-free corridor went east first, then moved west.

The theory has been that an ice-free corridor opened up east of the Rocky Mountains about 13,000 years ago, allowing the first Americans to migrate south.

She describes the traditional theory that the first Americans were the Clovis culture, who arrived through an ice-free corridor towards the end of the Ice Age 13,000 years ago.

During the 1950s, geologists first conjectured that an ice-free corridor ran north and south through Alberta during the Late Wisconsin period.

Some sites significantly predate the migration time frame of ice-free corridors, thus suggesting that there were additional coastal migration routes available, traversed either on foot and/or in boats.

These people were followed by the Clovis culture, which some archaeologists believe moved south from Alaska through an ice-free corridor located between modern British Columbia and Alberta.

These people are believed to have followed herds of now-extinct pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets.

The standard theory is that the people followed an ice-free corridor down through what is now Alberta into the western United States.

After the last glacial ice sheets melted from the northern parts of the Canadian prairies, an ice-free corridor allowed people from Asia to make a way deep into the Americas.

That's when ice sheets that had coalesced to cover the region about 10,000 years earlier melted enough to allow the animals to migrate through an ice-free corridor.