How are glaciers formed?

A glacier is a geographic feature made of ice.
Ice is formed from solid precipitation that falls and accumulates in the polar regions or above the snow line in the mountains. The lower layers of old snow gradually condense and crystallize, transforming into firn, an intermediate state between ice and snow. Subsequently, the firn is compacted under the influence of the higher layers, turning into white ice. The specialty ice, in turn, is transformed into glacier ice, consisting of ice transparent crystals, bluish in color.
The glacier is divided into two parts by a conventional line, called the recharge boundary. The area located above the supply line is called the accumulation zone. This is where the accumulation of ice mass occurs. Below the recharge boundary, there is a runoff area where the shape and mass of the glacier changes as a result of melting, evaporation or collapse.