At the peak of the last glaciation, some 18,000 years ago, ice covered our region to a depth of about 3,000 feet. That's right — the ice sheet was around half a mile high. All that weight greatly compressed the land, causing it to sink. As the glaciers began to recede from our region starting about 12,000 years ago, that weight was removed, causing the land to rebound. Recent measurements using Light Detection and Ranging (LIDAR) have shown the land near Hudson Bay to be rising about a half-inch per year.
Because the glaciers left our region sooner, the land around here has stopped rising. This means that the slope of the land from here to Hudson Bay is slowly decreasing. Eventually, this will cause the water in the Red River to stop flowing north. Because the Red River’s slope is from 2 to 6 inches per mile, it will take thousands of years before the Red River stops flowing. Perhaps the glaciers will return before then anyway.