are large sheets of ice that flow down very high mountains and are
often the source of snow-fed rivers. Glaciers, found mainly in places
such as Antarctica and Greenland, cover almost 10% of the earth's
landmass, varying in size. A glacier begins life as snowflakes. As
more snow falls and gathers, the weight of the snow on top compresses
the lower layers to form ice. The pile of snow and ice becomes thicker
and heavier till the point when the layer of ice at the very bottom
melts under the pressure. It re-freezes almost at once; but the process
is repeated over and over, and as a result the entire mass begins
to slide downhill slowly along the rock surface. A glacier has an
enormous impact on the topography of the area, pushing aside boulders,
cutting through rocks, and denting its path as it moves.
Most of the world's glaciers are found at the Poles, but they exist
on all of the world's continents, even Africa. Australia doesn't have
any glaciers; however, it is considered part of Oceania, which includes
several Pacific island chains and the large islands of Papua New Guinea
and New Zealand. Both of these islands have glaciers. Glaciers require
very specific geographical and climatic conditions. Most are found
in regions of high snowfall in winter and cool temperatures in summer.
The amount of precipitation (whether in the form of snowfall, freezing
rain, avalanches, or wind-drifted snow) is important to glacier survival.
In areas such as Siberia and parts of Antarctica, the lack of adequate
precipitation prevents glacier development.
At presently, about 10%
of the world's land area is covered with glaciers.
Glaciers store about 75%
of the world's freshwater.
Glacierized areas cover
over 15,000,000 square kilometres.
In the United States, glaciers
cover over 75,000 square kilometres, with most of the glaciers located
During the last Ice Age,
glaciers covered 32% of the total land area.
If all land ice melted,
the sea level would rise approximately 70 metres worldwide.
North America's longest
glacier is the Bering Glacier in Alaska, measuring 204 kilometres
The Malaspina Glacier in
Alaska is the world's largest piedmont glacier, covering over 8,000
square kilometres and measuring over 193 kilometers across at its
In India, glaciers are
found in the Himalayas. There are about 15,000 glaciers flowing through
these mountains, covering about 17% of the mountain area and supporting
numerous perennial rivers such as the Ganga, Indus, and Brahmaputra.
Some well-known glaciers are described below.
This glacier is believed to be as old as the Himalayan Mountains.
Dokriani 'Bamak' is a well-developed medium sized glacier of the Bhagirathi
basin. The glacier is 5 km long and flows in a northwest direction
terminating at an elevation of 3,800 m. It originates at an altitude
of 13 000 feet in Uttaranchal's Garhwal district. It is one of the
most studied glaciers in the world. A recent study says that it has
been shrinking by a few metres every year.
This is located in Uttaranchal's Tehri Garhwal. One of the oldest
glaciers in the Chaukhamba range, it is where the river Ganga originates.
The Gangotri is not a single valley glacier, but a combination of
several other glaciers that are fed to it and form a huge mass of
ice. The glacier covers 28km and terminates at Gaumukh (4,000m).
This is one of the most beautiful glaciers in the Kumaon hills and
is known as the Jewel of Kumaon. iIt is located at a height of 13
000 feet above sea level between the Nanda Devi and Nandakot peaks
and terminates at an altitude of 3,627 m. It is 5 km long, the snout
is about 6 m high and 2.5 m wide and above the snout, the glacier
extends for about 3m. The Pinder River that emerges from the Pindari
glacier drains the valley.
The Zemu glacier is the largest and most famous glacier in the eastern
Himalayas, with a length of about 26 km. It is located in northwestern
Sikkim in a U-shaped valley at the base of the Kanchenjunga massif.
The Teesta river has its source in this glacier.
Many tributary glaciers feed the trunk glacier.
This is the largest glacier in the world outside the Polar regions,
stretching over a length of about 72 km. It lies in the extreme north-
central part of Jammu and Kashmir near the border of India and Tibet,
on the north-facing slopes of the Karakoram Range, and feeds the Shaksgam
river that flows into Tibet. The glacier can be approached from Skardu
in Ladakh. To the east of the Siachen lies a group of three glaciers
known as the Rimo North, Central, and South. Between them, these glaciers
have almost 700 square km of ice, which, at places, is 100 m deep.
Altogether, the glaciers contain about 200 cubic kilometres of ice.