moulins

Moulin is the French word for a mill. In English-language discussion, moulins may refer to mills of European origin or to places named for mills. The term most commonly denotes structures that convert energy from water or wind into mechanical power, typically used to grind grain, drive saws, or supply other factory processes. Watermills rely on a flowing stream to turn a wheel, while windmills use wind to rotate blades.

In glaciology, moulin (plural moulins) designates a nearly vertical shaft through an ice sheet or glacier that channels meltwater from the surface down to the base. They form when surface water exploits cracks and shafts, enlarging them through erosion by moving water. Moulins can range from a few centimeters to several meters in diameter and may connect supraglacial lakes or streams to subglacial drainage systems. They influence glacier hydrology, base friction, and flow dynamics, and can produce rapid moulin outburst floods known as jökulhlaups in some systems.

These features are a focus of glaciological fieldwork and remote sensing. Their presence affects glacier melt rates and evolution. Moulins are found in many glaciated regions, including alpine and polar environments, where networks of moulins contribute to the drainage of supraglacial water and influence subglacial hydrology.