NALT Full

A sheet of very thick ice with a level or gently undulating surface. It is attached to the land on one side, but most of it is floating. On the seaward side, it is bounded by a steep cliff (ice front) 2 to 50 m or more above sea level. Ice shelves have formed along polar coasts (e.g., Antarctica and Greenland); they are very wide with some extending several hundreds of kilometers toward the sea from the coastline. They increase in size from annual snow accumulation and seaward extension of land glaciers. They decrease in size from warming, melting, and calving.