What does an ice-free corridor mean? About emigrating from the northwest coast to the United States

First of all, about 20,000 years ago, the ice age froze a lot of water in ice and glaciers, which led to a sharp drop in sea level. Then came the sea between Russia and Alaska, the Bering Strait.

A huge and accessible continental bridge. All kinds of animals, including mammals, bison, reindeer, etc. , began to migrate to America, and the humans who hunted them also migrated. In those days, a huge ice-free corridor,

One end passes through the Loki Mountains on one side of the Pacific Ocean and extends southward to all parts of the United States, while the other end goes deep into the vast Canadian land covered by continental ice.

-Clovis spearhead _ Baidu Encyclopedia