Glacial snow fields, also known as NEVE and FIRN, are accumulations of snow that have been compressed over time by the weight of additional snowfall. NEVE is a type of snow that has been partially melted and refrozen, while FIRN is a more compacted form of snow that has been partially melted and refrozen multiple times. Both NEVE and FIRN are important components of glaciers, as they provide the material from which glaciers form.