What is Glacier?
[[File:Baltoro glacier from air.jpg|thumb|The [[Baltoro Glacier]] in the Karakoram Mountains. {{convert|62|km|mi|0|lk=on}} in length, one of the longest alpine-type glaciers]] A '''glacier''' is a large body of [[ice]] and [[snow]]. It forms because the snow in an area does not all melt in [[summer]]. Each [[winter]], more snow is added. The [[weight]] of all the snow creates [[pressure]]. This pressure turns the lower parts of the snow into ice. After this happens for many years, the glacier will start growing large. It becomes so heavy that [[gravity]] causes the ice to move. It flows downwards like water but very slowly. A glacier only moves about {{convert|50|m|ft}} per year. New snowfalls replace the parts that flow away.<ref>{{cite book |first= Michael |last= Hambrey |author2= Alean, Jürg |title= Glaciers |url= https://archive.org/details/glaciers0002hamb |edition= 2nd |publisher= Cambridge University Press |year= 2004 |isbn= 0-521-82808-2 |oclc= 54371738}}</ref><ref>{{cite book |first= Douglas I. |last= Benn |author2= Evans, David J.A. |title= Glaciers and glaciation |publisher= Arnold |year= 1999 |isbn= 0470236515 |oclc= 38329570 }}</ref> Glaciers are the largest sources of [[freshwater|fresh water]] on Earth. The largest bodies of [[salt water]] are the [[Ocean|oceans]]. == Creation == [[File:Glaciers_and_Icebergs_at_Cape_York.jpg|thumb|Icebergs breaking off glaciers at Cape York, [[Greenland]]]] Glaciers will only form in places that are cold enough and get enough [[snow]] over time. This can take a long time. It often takes tens or hundreds of years for a glacier to form. There are two kinds of glaciers: ''continental glaciers'' and ''alpine glaciers''. Alpine glaciers are also called ''mountain glaciers''. * Continental glaciers are glaciers that spread out over a large area of land. They were created mostly during the [[Ice Age]]s a long time ago. There are still some continental glaciers in [[Greenland]] and [[Antarctica]]. They often flow downwards into the [[sea]] and break up. The broken part