What is a coulee?

The word coulee is derived from the French word 'couler' to flow and is used to describe a landform feature created by water erosion. Different regions of North America use the term to describe slightly different landforms.

The landscape of southern Manitoba shows many features of recent glaciation. The relatively level surface is created by deep layers of sediment laid down by enormous Lake Agassiz formed by the glacial meltwater. Through these layers of sediment, large channels have been carved by the immense rivers that eventually drained the meltwater to Hudson Bay. Many rivers now wind through the base of a channel that is far larger than their current flow.

Every spring, the winter snowpack melts, swelling the flow of rivers and streams. Where meltwater streams flows from the plain down the sides of these glacial river channels, water erosion cuts small sloping sided valleys. In drier areas, these channels only have surface water in them during the spring melt. These are called coulees.

A coulee is a deep narrow channel cut by rainstorms or melting snow.