Snow field

A snow field is an expanse of accumulated snow and ice, found typically above the snow line in mountainous and glacial terrain. It consists of old snow and neve, and snow that lasts longer than a year grows denser and is then called firn. Glaciers originate in snow fields. At the upper end of a glacier, and above its upper boundary, the snow field is an ice field covered with snow that transforms into firn, so the boundary where the glacier emerges from beneath the snow field is ill defined because the change is gradual. In summer the lower end of a glacier is usually free of snow and neve, while the upper end stays covered. A snow field is therefore the accumulation area from which a glacier is fed.