Location: Uttarakhand Map
Area: 1553 km2
The Gangotri Glacier is a glacier in the Indian state of
Uttarakhand, which is one of the largest glaciers in the Himalayas
with an estimated volume of over 27 km³. It is around 30 km long and
between 2 and 4 km wide; its area was around 144 km² in 2010.
The glacier's catchment area is framed by mountains of the
Gangotri group: the Chaukhamba (7138 m), Satopanth (7076 m),
Kedarnath (6940 m), Bhagirathi (6856 m), Janhukut (6805 m), Meru
(6672 m), Kharchakund (6612 m) and Shivling (6543 m). A number of
tributary glaciers feed the main river, the most important being the
Kirti Bamak, Ghanohim Bamak, Swachhand Bamak and Maiandi Bamak, plus
the lower-lying Raktavarn, Chaturangi and Meru glaciers, which are
no longer connected to the main glacier. Accumulation occurs
primarily in the winter months of December to March; the
contribution of snowfall during the summer monsoon is uncertain.
The Bhagirathi, one of the source rivers of the Ganges, rises
from the Gangotri glacier. The glacier gate is called Gaumukh
(roughly: “mouth of the cow”) by Hindus because of its former
appearance. As the main source of the Ganges, the glacier has great
religious significance in Hinduism and attracts thousands of
pilgrims every year. About 18 km or a day's walk away is the town of
Gangotri with the Ganga Temple, which is dedicated to the goddess
Ganga and is part of the Chota Char Dham pilgrimage route.
Even though large parts of the glacier in the ablation zone are
covered with rock debris - resulting in a delayed response to
climate changes - there is a significant retreat of the glacier. Due
to debris coverage and errors in the maps, information about the
retreat of the glacier varies greatly. Analysis of satellite images
by the United States Geological Survey showed a loss of more than
850 m in length between the early 1980s and the mid-2000s. An
analysis of satellite data from 2016 showed a lower retreat rate of
almost 18 m per year between 1965 and 2015, corresponding to a loss
in length of slightly less than 900 m. Main and secondary glaciers
lost a little more than 10 cm in thickness per year from 1968 to
2014 . While the decline in glacier length in the years before 2015
was less than the long-term average, the loss of mass was higher.
NASA, together with scientists from the United States Geological Survey (USGS) and the National Snow and Ice Data Center (NSIDC), is developing a global inventory of all the world's glaciers to help researchers trace the history of each one of them. According to them, the Gangotri glacier, which is currently 30.2 km long and 0.5 to 2.5 km wide, is one of the largest in the Himalayas. This glacier has not stopped retreating since measurements began in 1780. Data for 61 years (1936-96) showed that the total retreat of the Gangotri glacier was 1147 m, with an average rate of 19 m per year. However However, in the last 25 years of the 20th century it has retreated more than 850 meters (34 meters per year), and 76 meters between 1996 and 1999 (25 meters per year).
Gangotri is located in a glacial valley in the Uttarkashi district of
the Garhwal Himalayas in Uttarakhand. It flows towards the northwest. It
is bounded between the latitudes of 30° 43′ 22″ to 30° 55′ 49″ and the
longitudes of 79° 04′ 41″ to 79° 16′ 34″. Its altitude varies from 4,000
to 7,100 meters.
The total glacial cover is approximately 200 km2
and has a volume of approximately 20 km3 of ice.
This area is located north of the main central fault and is made up
of granite, different types of schists and gneiss.
The glacier is
composed of various depositional features such as scree cones, avalanche
cones, snow bridges and mounds of dead ice and erosion features.
Throughout the Gangotri Glacier, several longitudinal and transverse
crevasses were formed along which blocks of ice collapsed. The glacier
ablation zone is covered by a thick pile of supraglacial moraines and is
characterized by several sections of ice, which melt into supraglacial
lakes. Due to the rapid subsidence and degeneration of the glacier, its
center is filled with supraglacial lakes. In this part of the upper
Himalayas, glacial meltwater dominates the river system.
This glacier has three main tributaries: the Raktvarn (15.9 km), the Chaturangi (22.4 km, including the Kalandini bamak) and the Kirti (11 km); it also has over 18 smaller tributary glaciers. The Raktvarn glacial valley contains 7 tributary glaciers; among them, the Thelu, Swetvarn, Nilambar and Pilapani are important. Similarly, the Seeta, Suralaya and Vasuki are the main tributaries that make up the Chaturangi system, while the Kirti system has only three tributary glaciers. Besides these three major tributary systems, some other tributary glaciers in this region join directly with the Gangotri glacier; among them, Swachand, Miandi, Sumeru and Ghanohim are the most important. Four other glaciers, Maitri, Meru, Bhrigupanth and Manda, drain into the Bhagirathi River. The total glacial area of the catchment is 258.6 km2, of which 109 km2 is for the Gangotri system, followed by Chaturangi (72.9 km2), Raktvarn (45.3 km2) and Kirti (31.3 km2). The other four glaciers cover 29.4 km2 of glacial surface; among them, the Bhirgupanth glacier (15 km2) represents the largest part.
NASA, in collaboration with scientists from the United States Geological Survey and the National Snow and Ice Data Center, is developing a global inventory of all the world's glaciers to help researchers track the history of each glacier. According to them, the Gangotri glacier, which is currently 30.2 km long and between 0.5 and 2.5 km wide, is one of the largest in the Himalayas. This glacier has continued to retreat since measurements began in 1780. Data over 61 years (1936-96) showed that the total retreat of the glacier was 1,147 m, with an average rate of 19 m per year. During the last 25 years of the 20th century, it retreated by more than 850 meters (34 meters per year), and by 76 meters between 1996 and 1999 (25 meters per year).