An Underfit River in an Oversized Channel. The Evidence of a Catastrophic Flood.

The Minnesota River flows through a valley that dwarfs it entirely - a channel so vast relative to the modern river that geologists have a specific term for the mismatch. An underfit river is one diminutive relative to the channel it occupies, and Randall points to the Minnesota River as a textbook example. The channel was not carved by the river flowing through it today. It was the spillway of Lake Agassiz - a gigantic meltwater lake that formed during the deglaciation period - and the flow that carved it was of a scale that the modern landscape gives almost no indication of.

Geologists who have studied the site have concluded that the meltwater flow through this valley was approximately 4000 times greater than the current flow of the Minnesota River. The channel that remains is the physical scar of one of the most powerful flood events in North American geological history - and the relatively modest river flowing through it today is all that remains of a discharge that would have been incomprehensible to anyone standing in its path.

Step beyond the screen. Join Randall in the field and experience the evidence, landscapes, and history in person on his upcoming Finger Lakes tour Learn more here