A glacier is a large moving river of ice, made from snow that slowly moves by gravity. Glaciers are the largest part of freshwater on Earth. Almost two thirds of the worlds freshwater are trapped in glaciers. Much precipitation gets trapped in glaciers instead of flowing to the oceans, causing the sea levels to drop. The earth is pushed down by the weight of ice and that makes lakes form along the ice margins. Glaciers in mountain areas are called Alpine glaciers. Alpine glaciers are more commonly called valley glaciers. It is called a valley glacier because it looks like a valley in the mountains. A Continental glacier is a big chunk of ice which covers a lot of land near the Arctic and Antarctica regions. In the Arctic the continental glaciers form on frozen sea water. Continental glaciers formed a long time ago when snow fell millions of years ago and didn’t melt because the temperatures were above freezing. If the glacier comes to a river then crevasses will start to form in the glacier because of the stress of the ice. When the glacier reaches the ocean, the part of the glacier that breaks off is called an iceberg.