What are 2 forces caused by glaciers moving?

As glaciers move, they exert two primary forces: basal sliding and internal deformation. Basal sliding occurs when the glacier's weight and meltwater create lubrication at its base, allowing it to slide over the ground. Internal deformation involves the movement of ice within the glacier itself, where the weight causes the ice to flow and deform under pressure, leading to the glacier's overall advance or retreat. These forces shape the landscape, carving valleys and transporting sediments.