Antarctica is drained by outlet glaciers, ice streams, and ice shelves.
Most ablation occurs by calving or bottom melting of ice shelves.
An Ice stream is an area of rapidly flowing ice, bounded by slowly moving ice. Ice streams drain ice caps or ice sheets. Velocities of ice streams can be as high as 1-2 km per year. An outlet glacier is a flow of ice from an ice cap or ice sheet that is bounded by bedrock valley walls. The fastest flowing outlet glacier has a velocity of 8 km per year.