Ice calving from a glacier. When the terminus of a glacier occurs at the sea or a lake, the glacier is pushed out over the water. Eventually, the ice will collapse under its own weight, and millions of tons of ice will fall into the sea to form new icebergs. This process is called calving. This is the terminus of the Perito Moreno Glacier, at Lago Argentino (Argentino Lake) in Patagonia, Argentina. Photographed in September.