Glacier morphology, or the form a glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 takes, is influenced by temperature

Temperature

Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

, precipitation

Precipitation (meteorology)

In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...

, topography

Topography

Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...

, and other factors. Types of glaciers range from massive ice sheet

Ice sheet

An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² , thus also known as continental glacier...

s, such as the Greenland ice sheet

Greenland ice sheet

The Greenland ice sheet is a vast body of ice covering , roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after the Antarctic Ice Sheet. The ice sheet is almost long in a north-south direction, and its greatest width is at a latitude of 77°N, near its...

 or those in Antarctica, to small cirque glacier

Cirque glacier

A cirque glacier is formed in a cirque, bowl-shaped depressions on the side of or near mountains. Snow and ice accumulation in corries often occurs as the result of avalanching from higher surrounding slopes....

s perched on a mountain. Glaciers types can be grouped into two main categories, based on whether or not ice flow is constrained by the underlying bedrock

Bedrock

In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

 topography

Topography

Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...

.

Ice sheets and ice caps

Ice sheet

Ice sheet

An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² , thus also known as continental glacier...

s and ice cap

Ice cap

An ice cap is an ice mass that covers less than 50 000 km² of land area . Masses of ice covering more than 50 000 km² are termed an ice sheet....

s cover vast areas and are unconstrained by the underlying topography. The main distinction between the two is area, with ice caps covering areas less than 50,000 square kilometers, while ice sheets span larger areas. Ice sheets and ice caps can be classified further.

Ice domes

Ice domes located in the accumulation

Glacier ice accumulation

Glacier ice accumulation occurs through accumulation of snow and other frozen precipitation, as well as through other means including rime ice , avalanching from hanging glaciers on cliffs and mountainsides above, and re-freezing of glacier meltwater as superimposed ice...

 zone in the higher altitude portions.

Ice streams

Ice stream

Ice stream

An ice stream is a region of an ice sheet that moves significantly faster than the surrounding ice. Ice streams are a type of glacier. They are significant features of the Antarctic where they account for 10% of the volume of the ice...

s rapidly channel ice flow out to the sea or ocean

Ocean

An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

, where it may feed into an ice shelf

Ice shelf

An ice shelf is a thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland and Canada. The boundary between the floating ice shelf and the grounded ice that feeds it is called...

. At the margin between ice and water, ice calving

Ice calving

Ice calving, also known as glacier calving or iceberg calving, is a form of ice ablation or ice disruption. It is the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, ice shelf, or crevasse...

 takes place, with iceberg

Iceberg

An iceberg is a large piece of ice from freshwater that has broken off from a snow-formed glacier or ice shelf and is floating in open water. It may subsequently become frozen into pack ice...

s breaking off. Ice streams are bounded on the sides by areas of slowly moving ice.

Icefield

An icefield covers a relatively large area, usually located in mountainous terrain. The underlying topography controls or influences the form that an icefield takes. Often, nunatak

Nunatak

A nunatak is an exposed, often rocky element of a ridge, mountain, or peak not covered with ice or snow within an ice field or glacier. The term is typically used in areas where a permanent ice sheet is present...

s poke through the surface of icefields. Examples of icefields include the Columbia Icefield

Columbia Icefield

The Columbia Icefield is an icefield located in the Canadian Rockies, astride the Continental Divide of North America. The icefield lies partly in the northwestern tip of Banff National Park and the southern end of Jasper National Park. It is about 325 km² in area, 100 to 365 metres in depth and...

 in the Canadian Rockies

Canadian Rockies

The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...

 and the Northern and Southern Patagonian Ice Field

Southern Patagonian Ice Field

The Southern Patagonian Ice Field , located at the Southern Patagonic Andes between Argentina and Chile, is the second largest contiguous extrapolar extent of ice in the world...

 in Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

.

Outlet glaciers

Outlet glaciers are channels of ice that flow out of an ice sheet, but are constrained on the sides with exposed bedrock.

Valley glaciers

Valley glaciers, which provide drainage for icefields, are also constrained by underlying topography. Ice-free exposed bedrock and slopes often surround valley glaciers, providing snow and ice from above to accumulate on the glacier via avalanche

Avalanche

An avalanche is a sudden rapid flow of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack. Typically occurring in mountainous terrain, an avalanche can mix air and water with the...

s. True fjords are formed when valley glaciers retreat and water fills the void (due to land upheaval).

Cirque glaciers

Cirque glacier

Cirque glacier

A cirque glacier is formed in a cirque, bowl-shaped depressions on the side of or near mountains. Snow and ice accumulation in corries often occurs as the result of avalanching from higher surrounding slopes....

s form in cirque

Cirque (landform)

thumb|250 px|Two cirques with semi-permanent snowpatches in [[Abisko National Park]], [[Sweden]].A cirque or corrie is an amphitheatre-like valley head, formed at the head of a valley glacier by erosion...

, bowl-shaped depressions on the side of mountains. In these depressions, snow

Snow

Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...

 persists through summer months, and is transformed into glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

 ice. Snow may be situated on the leeward slope of a mountain, where it is sheltered.