Along portions of the Antarctic coast, glacial ice flows into the adjacent ocean, creating features called ice shelves. They are large, relatively flat masses of floating ice that extend seaward from the coast but remain attached to the land along one or more sides. The shelves are thickest on their landward sides, and they become thinner seaward. They are sustained by ice from the adjacent ice sheet as well as being nourished by snowfall and the freezing of seawater to their bases. Antarctica’s ice shelves extend over