glacier

thumb|upright=1.2|Glacier of the Geikie Plateau in Greenland thumb|upright=1.2|The Taschachferner in the Ötztal Alps in [[Austria. The mountain to the left is the Wildspitze (3.768 m), second highest in Austria]] thumb|upright=1.2|With 7,253 known glaciers, Pakistan contains more glaciers than any other country on Earth outside the polar regions. At in length, the pictured [[Baltoro Glacier is the fifth longest alpine glacier in the world.]] A glacier (; or ) is a persistent body of natural ice, a form of rock, that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It slowly flows and deforms under stresses induced by gravity, undergoing both ductile and brittle deformation, and acquiring distinguishing surface features, such as crevasses and seracs. As a glacier moves, it abrades underlying rock and debris to create glacial landforms, such as cirques, moraines, and fjords. Although a glacier may flow into a body of water, and can include ice shelves and ice tongues, it originates only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of freezing bodies of water.

On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Between latitudes 35°N and 35°S, glaciers occur only in the Himalayas, Andes, and a few high mountains in East Africa, Mexico, New Guinea and on Zard-Kuh in Iran. With more than 7,000 known glaciers, Pakistan has more glacial ice than any other country outside the polar regions. Glaciers cover about 10% of Earth's land surface. Continental glaciers cover nearly or about 98% of Antarctica's , with an average thickness of ice . Greenland and Patagonia also have huge expanses of continental glaciers. The volume of glaciers, not including the ice sheets of Antarctica and Greenland, has been estimated at 170,000 km3.