A glacier is a flowing mass of ice and rock on land.

interglacials

glaciations

For glaciers to form, there must be a year-round thick mass of snow which becomes compacted to form ice. Abundant snowfall and cool summers help this process.

Glacier de la Girose, Parc des Ecrins, France

SNOW

FIRN

ICE

Diagram courtesy Dr. Bruce Railsback, University of Georgia.

Diagram courtesy Dr. Bruce Railsback, University of Georgia

PATTERNS OF GLACIAL ICE FLOW