The loss of ice and snow from a glacier system. This can occur through processes like melting, calving and wind transportation of snow out of a glacier basin. The ablation area of a glacier lacks a snow cover in the warmer seasons. During those months, one can directly see the glacier ice.
The addition of ice and snow into a glacier system. The accumulation area of a glacier is covered in snow all year round, even in summer.
The process by which pieces of ice break away from the terminus of a glacier that ends in a body of water or from the edge of a floating ice shelf that ends in the ocean. Once they enter the water, the pieces are called icebergs.
The Equilibrium Line Altitude (ELA) is the elevation where accumulation of snow is exactly balanced by ablation over a period of a year.
A large, perennial accumulation of ice, snow, rock, sediment and liquid water originating on land and slowly moving down slope under the influence of its own weight and gravity; simply put, it is a river of ice.
A decrease in the length of a glacier compared to a previous point in time. As ice in a glacier is always moving forward, its frontal position retreats when more ice is lost at the terminus to melting and/or calving than reaches the terminus.