The Pech River ( Pashto : پېچ سيند ) is located in eastern Afghanistan .
150-709: The Pech River system is fed from glaciers and snow from the Hindu Kush range to its north. The river rises in central Nuristan Province and flows south and southeasterly through the center of Kunar Province , joining the Kunar River (Asmar River, Loy Seend ) at the provincial capital of Asadabad . The Kunar is a tributary of the Kabul River , part of the Indus River basin. The river has numerous tributaries forming valleys on both sides. These include
300-424: A cirque landform (alternatively known as a corrie or as a cwm ) – a typically armchair-shaped geological feature (such as a depression between mountains enclosed by arêtes ) – which collects and compresses through gravity the snow that falls into it. This snow accumulates and the weight of the snow falling above compacts it, forming névé (granular snow). Further crushing of the individual snowflakes and squeezing
450-522: A glacier is usually assessed by determining the glacier mass balance or observing terminus behavior. Healthy glaciers have large accumulation zones, more than 60% of their area is snow-covered at the end of the melt season, and they have a terminus with a vigorous flow. Following the Little Ice Age 's end around 1850, glaciers around the Earth have retreated substantially . A slight cooling led to
600-601: A glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of 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
750-411: A glacier via moulins . Streams within or beneath a glacier flow in englacial or sub-glacial tunnels. These tunnels sometimes reemerge at the glacier's surface. Most of the important processes controlling glacial motion occur in the ice-bed contact—even though it is only a few meters thick. The bed's temperature, roughness and softness define basal shear stress, which in turn defines whether movement of
900-408: A kilometer per year. Eventually, the ice will be surging fast enough that it begins to thin, as accumulation cannot keep up with the transport. This thinning will increase the conductive heat loss, slowing the glacier and causing freezing. This freezing will slow the glacier further, often until it is stationary, whence the cycle can begin again. The flow of water under the glacial surface can have
1050-404: A large effect on the motion of the glacier itself. Subglacial lakes contain significant amounts of water, which can move fast: cubic kilometers can be transported between lakes over the course of a couple of years. This motion is thought to occur in two main modes: pipe flow involves liquid water moving through pipe-like conduits, like a sub-glacial river; sheet flow involves motion of water in
1200-516: A location is dependent on the season, orientation and bearing with respect to the Sun , and the mass of the mountain. As the Sun is the major contributor to the temperature, it is often directly proportional to the received radiation from the Sun with faces receiving more sunlight having a higher heat buildup. In narrow valleys between steep mountain faces, the weather conditions may differ significantly on both
1350-460: A lower heat conductance, meaning that the basal temperature is also likely to be higher. Bed temperature tends to vary in a cyclic fashion. A cool bed has a high strength, reducing the speed of the glacier. This increases the rate of accumulation, since newly fallen snow is not transported away. Consequently, the glacier thickens, with three consequences: firstly, the bed is better insulated, allowing greater retention of geothermal heat. Secondly,
1500-495: A notable increase in the rate of glacier retreat across the region as a result of climate change. The rate of retreat varies across regions depending on the local conditions. Since 1975, a marked increase in the loss of glacial mass from 5–13 Gt/yr to 16–24 Gt/yr has been observed with an estimated 13% overall decrease in glacial coverage in the Himalayas. The resulting climate variations and changes in hydrology could affect
1650-488: A thin layer. A switch between the two flow conditions may be associated with surging behavior. Indeed, the loss of sub-glacial water supply has been linked with the shut-down of ice movement in the Kamb ice stream. The subglacial motion of water is expressed in the surface topography of ice sheets, which slump down into vacated subglacial lakes. The speed of glacial displacement is partly determined by friction . Friction makes
SECTION 10
#17328015423301800-410: A tremendous impact as the iceberg strikes the water. Tidewater glaciers undergo centuries-long cycles of advance and retreat that are much less affected by climate change than other glaciers. Thermally, a temperate glacier is at a melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below the freezing threshold from the surface to its base, although
1950-824: Is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau . The range has several peaks exceeding an elevation of 8,000 m (26,000 ft) including Mount Everest , the highest mountain on Earth. The mountain range runs for 2,400 km (1,500 mi) as an arc from west-northwest to east-southeast at the northern end of the Indian subcontinent. The Himalayas occupy an area of 595,000 km (230,000 sq mi) across six countries – Afghanistan , Bhutan , China , India , Nepal , and Pakistan . The sovereignty of
2100-468: Is a persistent body of dense ice that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries . It acquires distinguishing features, such as crevasses and seracs , as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques , moraines , or fjords . Although
2250-456: Is above or at freezing at the interface and is able to slide at this contact. This contrast is thought to a large extent to govern the ability of a glacier to effectively erode its bed , as sliding ice promotes plucking at rock from the surface below. Glaciers which are partly cold-based and partly warm-based are known as polythermal . Glaciers form where the accumulation of snow and ice exceeds ablation . A glacier usually originates from
2400-407: Is affected by factors such as slope, ice thickness, snowfall, longitudinal confinement, basal temperature, meltwater production, and bed hardness. A few glaciers have periods of very rapid advancement called surges . These glaciers exhibit normal movement until suddenly they accelerate, then return to their previous movement state. These surges may be caused by the failure of the underlying bedrock,
2550-716: Is also the source of major streams of the Ganges river system. The Eastern Himalayas form the eastern most stretch of the range and consist of the states of parts of Tibet in China, Sikkim , Assam , Arunachal Pradesh , parts of other North East Indian states and north West Bengal in India, entirety of Bhutan, mountain regions of central and eastern Nepal, and most of the western lowlands in Nepal. The eastern Himalayas broadly consists of two regions–the western Nepal Himalayas and
2700-518: Is among the highest in the world, at typically around 5,500 m (18,000 ft) while several equatorial mountains such as in New Guinea , the Rwenzoris , and Colombia , have a snow line at 900 m (3,000 ft) lower. As the physical features of mountains are irregular, with broken jagged contours, there can be wide variations in temperature over short distances. The temperature at
2850-479: Is amongst the most affected regions due to climate change . Since the late 20th century, scientists have reported a notable increase in the rate of glacier retreat and changes occurring at a far rapid rate. As per a 2019 assessment, the Himalayan region, which had experienced a temperature rise of 0.1 °C (32.2 °F) per decade was warming at an increased rate of 0.1 °C (32.2 °F) per decade over
3000-411: Is because these peaks are located near or in the hyperarid Atacama Desert . Glaciers erode terrain through two principal processes: plucking and abrasion . As glaciers flow over bedrock, they soften and lift blocks of rock into the ice. This process, called plucking, is caused by subglacial water that penetrates fractures in the bedrock and subsequently freezes and expands. This expansion causes
3150-406: Is by basal sliding, where meltwater forms between the ice and the bed itself. Whether a bed is hard or soft depends on the porosity and pore pressure; higher porosity decreases the sediment strength (thus increases the shear stress τ B ). Porosity may vary through a range of methods. Bed softness may vary in space or time, and changes dramatically from glacier to glacier. An important factor
SECTION 20
#17328015423303300-434: Is called glaciology . Glaciers are important components of the global cryosphere . Glaciers are categorized by their morphology, thermal characteristics, and behavior. Alpine glaciers form on the crests and slopes of mountains. A glacier that fills a valley is called a valley glacier , or alternatively, an alpine glacier or mountain glacier . A large body of glacial ice astride a mountain, mountain range, or volcano
3450-416: Is called rock flour and is made up of rock grains between 0.002 and 0.00625 mm in size. Abrasion leads to steeper valley walls and mountain slopes in alpine settings, which can cause avalanches and rock slides, which add even more material to the glacier. Glacial abrasion is commonly characterized by glacial striations . Glaciers produce these when they contain large boulders that carve long scratches in
3600-492: Is followed by monsoon rains from June to September. The post monsoon season is largely devoid of rain and snow before beginning of cold winters in December-January with intermediate spring before the summer. There are localised wind pressure systems at high altitudes resulting in heavy winds. Due to its high altitude, the range blocks the flow of cold winds from the north into the Indian subcontinent. This causes
3750-603: Is found in the mixed deciduous and conifer forests of the Eastern Himalayas and the Himalayan water shrew are found on the river banks. The forests of the foothills are inhabited by several different primates, including the endangered Gee's golden langur and the Kashmir gray langur , within highly restricted ranges in the east and west of the Himalayas, respectively. The yaks are large domesticated cattle found in
3900-647: Is higher, and the mountains above 5,000 m (16,400 ft) usually have permanent snow. Even at high latitudes, glacier formation is not inevitable. Areas of the Arctic , such as Banks Island , and the McMurdo Dry Valleys in Antarctica are considered polar deserts where glaciers cannot form because they receive little snowfall despite the bitter cold. Cold air, unlike warm air, is unable to transport much water vapor. Even during glacial periods of
4050-560: Is home to more than a billion people. In 2011, the population in the Himalayan region was estimated to be about 52.8 million with the combined drainage basin of the Himalayan rivers home to nearly 600 million. Of this, 7.96 million (15.1% of the total Himalayan population) live in Eastern Himalayas, 19.22 million in Central Himalayas (36.4%), and 25.59 million reside in Western Himalayas (48.5%). The population of
4200-614: Is one of the youngest mountain ranges on the planet and consists of uplifted sedimentary and metamorphic rock . According to the modern theory of plate tectonics , it was formed as a result of a continental collision and orogeny along the convergent boundary between the India and Eurasian Plates . During the Jurassic period (201 to 145 mya ), the Tethys Ocean formed the southern border of then existent Eurasian landmass. When
4350-897: Is termed an ice cap or ice field . Ice caps have an area less than 50,000 km (19,000 sq mi) by definition. Glacial bodies larger than 50,000 km (19,000 sq mi) are called ice sheets or continental glaciers . Several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces. The only extant ice sheets are the two that cover most of Antarctica and Greenland. They contain vast quantities of freshwater, enough that if both melted, global sea levels would rise by over 70 m (230 ft). Portions of an ice sheet or cap that extend into water are called ice shelves ; they tend to be thin with limited slopes and reduced velocities. Narrow, fast-moving sections of an ice sheet are called ice streams . In Antarctica, many ice streams drain into large ice shelves . Some drain directly into
4500-580: Is the lower middle sub-section of the Himalayas. It extends almost along the entire length of the Himalayas and is about 75 km (47 mi) wide. It is mostly composed of rocky surfaces and has an average elevation of 3,700–4,500 m (12,100–14,800 ft). The Greater Himalayas (also known as Himadri ) form the highest section of the Himalayas and extend for about 2,300 km (1,400 mi) from northern Pakistan to northern Arunachal Pradesh in India. The sub-range has an average elevation of more than 6,100 m (20,000 ft) and contains many of
4650-413: Is the region where there is a net loss in glacier mass. The upper part of a glacier, where accumulation exceeds ablation, is called the accumulation zone . The equilibrium line separates the ablation zone and the accumulation zone; it is the contour where the amount of new snow gained by accumulation is equal to the amount of ice lost through ablation. In general, the accumulation zone accounts for 60–70% of
Pech River - Misplaced Pages Continue
4800-402: Is the underlying geology; glacial speeds tend to differ more when they change bedrock than when the gradient changes. Further, bed roughness can also act to slow glacial motion. The roughness of the bed is a measure of how many boulders and obstacles protrude into the overlying ice. Ice flows around these obstacles by melting under the high pressure on their stoss side ; the resultant meltwater
4950-552: Is then forced into the cavity arising in their lee side , where it re-freezes. As well as affecting the sediment stress, fluid pressure (p w ) can affect the friction between the glacier and the bed. High fluid pressure provides a buoyancy force upwards on the glacier, reducing the friction at its base. The fluid pressure is compared to the ice overburden pressure, p i , given by ρgh. Under fast-flowing ice streams, these two pressures will be approximately equal, with an effective pressure (p i – p w ) of 30 kPa; i.e. all of
5100-755: The Andaman Sea . The Salween , Mekong , Yangtze , and Yellow Rivers all originate from parts of the Tibetan Plateau, north of the great water divide. These are considered distinct from the Himalayan watershed and are known as circum-Himalayan rivers. The Himalayan region has multiple lakes across various elevations including endorheic freshwater and saline lakes . The geology of the lakes vary across geographies depending on various factors such as altitude, climate, water source, and lithology . Tarns are high altitude mountain lakes situated above 5,500 m (18,000 ft) and are formed primarily by
5250-993: The Andes , the Himalayas , the Rocky Mountains , the Caucasus , Scandinavian Mountains , and the Alps . Snezhnika glacier in Pirin Mountain, Bulgaria with a latitude of 41°46′09″ N is the southernmost glacial mass in Europe. Mainland Australia currently contains no glaciers, although a small glacier on Mount Kosciuszko was present in the last glacial period . In New Guinea, small, rapidly diminishing, glaciers are located on Puncak Jaya . Africa has glaciers on Mount Kilimanjaro in Tanzania, on Mount Kenya , and in
5400-567: The Bay of Bengal were also formed as a result of the same tectonic processes that formed the Himalayas. The Indian plate continues to be driven horizontally at the Tibetan Plateau at about 67 mm (2.6 in) per year, forcing it to continue to move upwards. About 20 mm (0.79 in) per year is absorbed by thrusting along the Himalaya southern front , which leads to the Himalayas rising by about 5 mm (0.20 in) per year. This makes
5550-663: The Dihang River to the India-Tibet border. The highest peak is the eastern anchor Namcha Barwa at 7,756 m (25,446 ft). The region is the source of many of the tributaries of the Brahmaputra River and consists of major mountain passes such as Nathu La , and Jelep La . Beyond the Dihang valley, the mountains extend as Purvanchal mountain range across the eastern boundary of India. The Himalayan range
5700-490: The Everest . At lower altitudes, the temperature is pleasantly warm during the summers. During winters, the low-pressure weather systems from the west cause heavy snowfall . There are two periods of precipitation with most of the rainfall occurring during the post summer season and moderate amount during the winter storms. The Himalayan range obstructs the path of the south west monsoon winds, causing heavy precipitation on
5850-644: The Faroe and Crozet Islands were completely glaciated. The permanent snow cover necessary for glacier formation is affected by factors such as the degree of slope on the land, amount of snowfall and the winds. Glaciers can be found in all latitudes except from 20° to 27° north and south of the equator where the presence of the descending limb of the Hadley circulation lowers precipitation so much that with high insolation snow lines reach above 6,500 m (21,330 ft). Between 19˚N and 19˚S, however, precipitation
6000-760: 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 13 million km (5 million sq mi) or about 98% of Antarctica 's 13.2 million km (5.1 million sq mi), with an average thickness of ice 2,100 m (7,000 ft). Greenland and Patagonia also have huge expanses of continental glaciers. The volume of glaciers, not including
6150-761: The Indian epic Mahabharata , which is the personification of the Hindu deity Himavan . The mountain range is known as Himālaya in Hindi and Nepali (both written हिमालय ), Himalaya ( ཧི་མ་ལ་ཡ་ ) in Tibetan , Himāliya ( سلسلہ کوہ ہمالیہ ) in Urdu , Himaloy ( হিমালয় ) in Bengali , and Ximalaya ( simplified Chinese : 喜马拉雅 ; traditional Chinese : 喜馬拉雅 ; pinyin : Xǐmǎlāyǎ ) in Chinese . It
Pech River - Misplaced Pages Continue
6300-520: The Indian subcontinent and the regions north of the range. The mountains are spread across more than eight degrees of latitude and hence includes a wide range of climatic zones including sub-tropical , temperate , and semi-arid . The climate in a region is determined by factors such as altitude, latitude, and the impact on monsoon. There are generally five seasons: summer, monsoon, autumn or post-monsoon, winter, and spring. The summer in April-May
6450-602: The Kashmir valley . The higher elevations consist of rock fragements and lithosols with very low humus content. The Himalayas and the Central Asian mountain ranges consist of the third-largest deposit of ice and snow in the world, after the Antarctic and Arctic regions. It is often referred to as the "Third Pole" as it encompasses about 15,000 glaciers, which store about 12,000 km (2,900 cu mi) of fresh water. The South Col and Khumbu Glacier in
6600-516: The Kumaon region. The northern extremes of the Great Himalayas in Kashmir and Ladakh receive only 3–6 in (76–152 mm) of rainfall per year. During the winter season, a high pressure system develops over Central Asia, which results in winds flowing towards the Himalayas. However, due to the presence of less water bodies in the Central Asian region, the moisture content is low. As
6750-1272: The Main Frontal Thrust and the Main Boundary Thrust (MBT); the Lesser Himalayan Zone between the MBT and the Main Central Thrust (MCT); the Higher Himalayan Zone beyond the MCT; the Tethyan Zone, separated by the South Tibetan Detachment System; and the Indus-Tsangpo Suture Zone, where the Indian plate is subducted below the Asian plate. The Arakan Yoma highlands in Myanmar and the Andaman and Nicobar Islands in
6900-481: The Mount Everest region are amongst the world's highest glaciers. The Gangotri which is 32 km (20 mi) long and is one of the largest glaciers, is one of the sources of the Ganges . The Himalayan glaciers show considerable variation in the rate of descent. The Khumbu moves about 1 ft (0.30 m) daily compared to certain other glaciers which move about 6 ft (1.8 m) per day. During
7050-454: The Paris agreement , aimed at climate change mitigation and adaptation . The actions are aimed at reducing emissions , increase the usage of renewable energy , and sustainable environmental practices. As the local population increasingly experience the impact of the changes in climate such as variations in temperature and precipitation, and change in vegetation, they are forced to adapt for
7200-562: The Quaternary , Manchuria , lowland Siberia , and central and northern Alaska , though extraordinarily cold, had such light snowfall that glaciers could not form. In addition to the dry, unglaciated polar regions, some mountains and volcanoes in Bolivia, Chile and Argentina are high (4,500 to 6,900 m or 14,800 to 22,600 ft) and cold, but the relative lack of precipitation prevents snow from accumulating into glaciers. This
7350-535: The Rwenzori Mountains . Oceanic islands with glaciers include Iceland, several of the islands off the coast of Norway including Svalbard and Jan Mayen to the far north, New Zealand and the subantarctic islands of Marion , Heard , Grande Terre (Kerguelen) and Bouvet . During glacial periods of the Quaternary, Taiwan , Hawaii on Mauna Kea and Tenerife also had large alpine glaciers, while
7500-738: The Sivalik Hills on the south; the Lower Himalayas ; the Great Himalayas , which is the highest and central range; and the Tibetan Himalayas on the north. The Sivalik Hills form the lowest sub-Himalayan range and extends for about 1,600 km (990 mi) from the Teesta River in the Indian state of Sikkim to northern Pakistan. The name derives from Sanskrit meaning "Belonging to Shiva ", which
7650-542: The Western Himalayas has characteristics of species from Central Asia and Mediterranean region. Fossils of species such as giraffe , and hippopotamus have been found in the foothills, suggesting the presence of African species some time ago. Large mammals such as Indian elephant , and Indian rhinoceros are confined to the densely forested moist ecosystems in the Eastern and Central Himalayas. Many of
SECTION 50
#17328015423307800-473: The Yarlung Tsangpo River . The Himalayas consists of four parallel mountain ranges: the Sivalik Hills on the south; the Lower Himalayas ; the Great Himalayas , which is the highest and central range; and the Tibetan Himalayas on the north. The range varies in width from 350 km (220 mi) in the north-west to 150 km (93 mi) in the south-east. The Himalayan range is one of
7950-517: The Zanskar , Pir Panjal Ranges , and parts of the Sivalik and Great Himalayas. The western anchor Nanga Parbat is the highest point in the region at 8,126 m (26,660 ft). It is also referred Punjab, Kashmir or Himachal Himalyas from west to east locally. The central Himalayas or Kumaon extend for about 320 km (200 mi) along the state of Uttarakhand in northern India from
8100-631: The last ice age , there was a connected ice stream of glaciers between Kangchenjunga in the east and Nanga Parbat in the west. The glaciers joined with the ice stream network in the Karakoram in the west, the Tibetan inland ice in the north, and came to an end below an elevation of 1,000–2,000 m (3,300–6,600 ft) in the south. While the current valley glaciers of the Himalaya reach at most 20–32 km (12–20 mi) in length, several of
8250-410: The 18th century till the independence of the constituent states in the mid 20th century. The long history along with various outside influences have resulted in the mixture of various traditions and existence of wide range of ethnicity in the region. People speak various languages belonging to four principal language families– Indo-European , Tibeto-Burman , Austroasiatic , and Dravidian , with
8400-448: The 1990s and 2000s. In a study using data from January 1993 through October 2005, more events were detected every year since 2002, and twice as many events were recorded in 2005 as there were in any other year. Ogives or Forbes bands are alternating wave crests and valleys that appear as dark and light bands of ice on glacier surfaces. They are linked to seasonal motion of glaciers; the width of one dark and one light band generally equals
8550-578: The ANA in control of and the establishment of ANA Fire bases in and along the area that COP Michigan was the U.S. Army's 4th Infantry Division 's 4th Brigade Combat Team. U.S. President Barack Obama then pulled the American forces from the valley again, ceding it to the Taliban due to the questionable ability and loyalty of the ANA. The 2012 book Siren's Song: The Allure of War , by Antonio Salinas, depicts
8700-457: The Brahmaputra river system from the Tibetan rivers to the north. There are 19 major rivers in the Himalayas which form part of the two major river systems of Ganges - Brahmaputra , which follow an easterly course and Indus , which follows a north-westerly course. The northern slopes of Gyala Peri and the peaks beyond the Tsangpo drain into the Irrawaddy River , which originates in eastern Tibet and flows south through Myanmar to drain into
8850-414: The Chapa Dara, Waygal, Korangal Valley (site of the film Restrepo ), Watapur , and Sharyak valleys. In the Pech Valley, Pashto and the Askunu languages are spoken. The Safi tribe of Pashtuns is the majority population in the Pech Valley. The river's largest settlement is Nangalam , at the confluence of the Waygal River with the Pech River. There were a series of U.S. military bases along
9000-420: The Himalayan lakes present the danger of a glacial lake outburst flood as they have grown considerably over the last 50 years due to glacial melting. While these lakes support a range of ecosystems and local communities, many of them remain poorly studied in terms of their hydrology and biodiversity. Due to its location and size, the Himalayas acts as a climatic barrier which affects the weather conditions of
9150-413: The Himalayan region geologically active and the movement of the Indian plate into the Asian plate makes the region seismically active, leading to earthquakes from time to time. The northern slopes of the Himalayas have a thicker soil cover than the southern slopes due to presence of lesser number of rivers and streams. These soils are loamy and are dark brown in colour, and are covered with forests in
SECTION 60
#17328015423309300-531: The Himalayan region including Bhutan, Nepal, Bangladesh, India, and Pakistan are amongst the most vulnerable countries in the Global South due to climate change. The temperature rise increases the incidence of tropical diseases such as malaria , and dengue further north. The extreme weather events might cause physical harm directly and indirectly due to lack of access and contamination of drinking water , pollution , exposure to chemicals, and destruction of crops, and drought . The climate change also impact
9450-420: The Himalayan region occurred in 2000 BCE when Aryans came from Central Asia and progressively settled along the plains to the south. Information on the Aryan culture in the region is found in Hindu literature such as the Vedas , and Puranas . Since the second century BCE, the Silk Road in China was connected to the Indian subcontinent by various routes running along the Himalayan region. The northern side of
9600-433: The Himalayan waters. The extremes of high altitude favor the presence of extremophile organisms, which include various species of insects such as spiders , and mites . The Himalayan fauna include endemic plants and animals and critically endangered or endangered species such as Indian elephant, Indian rhinoceros, musk deer and hangul . There are more than 7,000 endemic plants and 1.9% of global endemic vertebrates in
9750-426: The Himalayas has grown considerably over the last five decades from 19.9 million in 1961 with the annual growth rate (3.31%) more than three times higher than the world average (1.1%) during the same period. The earliest tribes in the Himalayas might have originated from Dravidian people from the south of the Indian subcontinent as evidenced by the presence of Dravidian languages . The major human migration towards
9900-447: The Himalayas reduce by 2 °C (36 °F) for every 300 m (980 ft) increase of altitude. Higher altitudes invariably experience low temperatures. In the Eastern Himalayas, Darjeeling at an altitude of 1,945 m (6,381 ft) has an average minimum temperature of 11 °C (52 °F) during the month of May, while the same has been recorded as −22 °C (−8 °F) at an altitude of 5,000 m (16,000 ft) on
10050-425: The Himalayas was under the influence of various Tibetan kingdoms across history. In the middle ages , the southern side came under the influence of various Rajput kings and later under the Mughal rule . Nepal was ruled by various kingdoms from both the Indian and Tibetan regions, until it was conquered by the Gurkha kingdom in the early 18th century. Most of the southern region came under the British influence in
10200-617: The Indian Himalayas. Pangong Lake spread across India and China is the highest saline lake in the world at an altitude of 4,350 m (14,270 ft) and amongst the largest in the region with a surface area of 700 km (270 sq mi). Spread across 189 km (73 sq mi), Wular Lake is amongst the largest fresh water lakes in Asia. Other large lakes include Tso Moriri , and Tso Kar in Ladakh , Nilnag , and Tarsar Lake , in Jammu and Kashmir , Gurudongmar , Chholhamu , and Tsomgo Lakes in Sikkim , Tilicho , Rara , Phoksundo , and Gokyo Lakes in Nepal. Some of
10350-422: The Pech River Valley in Kunar Province, including COP Honaker-Miracle, COP Able Main, COP Michigan, and the largest − FOB Blessing. Most were closed after 2011. In 2011 former FOB Blessing was abandoned by the Afghan National Army (ANA) , and the 25th Infantry Division returned to reestablish the area of influence. The new name was COP Nangalam, with a majority of control in the hands of the ANA. In late 2012 with
10500-487: The Sutlej River in the east to the Kali River in the west. The region comprises parts of Sivalik and Great Himalayas. At lower elevations below 2,400 m (7,900 ft), the region has a temperate climate and consists of permanent settlements. At elevations higher than 4,300 m (14,100 ft), permanent snow caps cover the Great Himalayas with the highest peaks being Nanda Devi at 7,817 m (25,646 ft) and Kamet at 7,756 m (25,446 ft). The region
10650-411: The Tethys ocean. The upliftment of the Himalayas occurred gradually and as the Great Himalayas became higher, they became a climatic barrier and blocked the winds, which resulted in lesser precipitation on the upper slopes. The lower slopes continued to be eroded by the rivers, which flowed in the gaps between the mountains and the folded lower Shivalik Hills and the Lesser Himalayas were formed due to
10800-605: The Tibetan Himalayas and the plateau beyond. It also played a role in the formation of Central Asian deserts such as the Taklamakan and Gobi . The monsoon is triggered by the different rates of heating and cooling between the Indian Ocean and Central Asia, which create large differences in the atmospheric pressure prevailing above each. As the Central Asian landmass heats up during the summer compared to
10950-534: The Western Himalayas. The high altitude mountainous areas are mostly barren or, at the most, sparsely sprinkled with stunted bushes. The Himalayas are home to various medicinal plants such as Abies pindrow used to treat bronchitis , Andrachne cordifolia used for snake bites , and Callicarpa arborea used for skin diseases . Nearly a fifth of the plant species in the Himalayas are used for medicinal purposes. Climate change , illegal deforestation , and introduction of non native species have had an effect on
11100-412: The advance of many alpine glaciers between 1950 and 1985, but since 1985 glacier retreat and mass loss has become larger and increasingly ubiquitous. Glaciers move downhill by the force of gravity and the internal deformation of ice. At the molecular level, ice consists of stacked layers of molecules with relatively weak bonds between layers. When the amount of strain (deformation) is proportional to
11250-520: The air from the snow turns it into "glacial ice". This glacial ice will fill the cirque until it "overflows" through a geological weakness or vacancy, such as a gap between two mountains. When the mass of snow and ice reaches sufficient thickness, it begins to move by a combination of surface slope, gravity, and pressure. On steeper slopes, this can occur with as little as 15 m (49 ft) of snow-ice. In temperate glaciers, snow repeatedly freezes and thaws, changing into granular ice called firn . Under
11400-430: The amount of melting at surface of the glacier, the faster the ice will flow. Basal sliding is dominant in temperate or warm-based glaciers. The presence of basal meltwater depends on both bed temperature and other factors. For instance, the melting point of water decreases under pressure, meaning that water melts at a lower temperature under thicker glaciers. This acts as a "double whammy", because thicker glaciers have
11550-455: The animal species found in the region are unique and endemic or nearly endemic to the region. Other large animal species found in the Himalayas include Asiatic black bear , clouded leopard , and herbivores such as bharal , Himalayan tahr , takin , Himalayan serow , Himalayan musk deer , and Himalayan goral . Animals found at higher altitudes include brown bear , and the elusive snow leopard , which mainly feed on bharal. The red panda
11700-713: The annual movement of the glacier. Ogives are formed when ice from an icefall is severely broken up, increasing ablation surface area during summer. This creates a swale and space for snow accumulation in the winter, which in turn creates a ridge. Sometimes ogives consist only of undulations or color bands and are described as wave ogives or band ogives. Glaciers are present on every continent and in approximately fifty countries, excluding those (Australia, South Africa) that have glaciers only on distant subantarctic island territories. Extensive glaciers are found in Antarctica, Argentina, Chile, Canada, Pakistan, Alaska, Greenland and Iceland. Mountain glaciers are widespread, especially in
11850-432: The bedrock has frequent fractures on the surface, glacial erosion rates tend to increase as plucking is the main erosive force on the surface; when the bedrock has wide gaps between sporadic fractures, however, abrasion tends to be the dominant erosive form and glacial erosion rates become slow. Glaciers in lower latitudes tend to be much more erosive than glaciers in higher latitudes, because they have more meltwater reaching
12000-445: The bedrock. By mapping the direction of the striations, researchers can determine the direction of the glacier's movement. Similar to striations are chatter marks , lines of crescent-shape depressions in the rock underlying a glacier. They are formed by abrasion when boulders in the glacier are repeatedly caught and released as they are dragged along the bedrock. The rate of glacier erosion varies. Six factors control erosion rate: When
12150-661: The bend of the Indus River along the Pakistan-Afghanistan border region in the north-west to the Satlej river basin in India in the south-east. Most of the region lies in the Kashmir territory disputed between India and Pakistan with certain portions of the Indian state of Himachal Pradesh . The Indus forms the division between the Western Himalayas and the Karakoram range to the north. The Western Himalayas include
12300-510: The cold winds from Central Asia , and plays a significant roles in influencing the monsoons . The vast size, varying altitude range, and complex topography of the Himalayas result in a wide range of climates, from humid and subtropical to cold and dry desert conditions. The mountains have profoundly shaped the cultures of South Asia and Tibet . Many Himalayan peaks are considered sacred across various Indian and Tibetan religions such as Hinduism , Buddhism , Jainism , and Bon . Hence,
12450-453: The condensation occurs at higher altitudes in the north, there is more precipitation in the Great Himalayas in the west during the winter rains and the precipitation reduces towards the east. In January, the Kumaon region receives about 3 in (76 mm) of rainfall compared to about 1 in (25 mm) in the Eastern Himalayas. The Himalayan region has a highly sensitive ecosystem and
12600-571: The created ice's density. The word glacier is a loanword from French and goes back, via Franco-Provençal , to the Vulgar Latin glaciārium , derived from the Late Latin glacia , and ultimately Latin glaciēs , meaning "ice". The processes and features caused by or related to glaciers are referred to as glacial. The process of glacier establishment, growth and flow is called glaciation . The corresponding area of study
12750-467: The deep profile of fjords , which can reach a kilometer in depth as ice is topographically steered into them. The extension of fjords inland increases the rate of ice sheet thinning since they are the principal conduits for draining ice sheets. It also makes the ice sheets more sensitive to changes in climate and the ocean. Although evidence in favor of glacial flow was known by the early 19th century, other theories of glacial motion were advanced, such as
12900-483: The deformation to become a plastic flow rather than elastic. Then, the glacier will begin to deform under its own weight and flow across the landscape. According to the Glen–Nye flow law , the relationship between stress and strain, and thus the rate of internal flow, can be modeled as follows: where: The lowest velocities are near the base of the glacier and along valley sides where friction acts against flow, causing
13050-475: The downwarping of the intermediate lands. Minor streams ran between the faults within the mountains until they joined the major river systems in the plains. Intermediate valleys such as Kashmir and Kathmandu were formed from temporary lakes that were formed during pleistocene , which dried up later. The Himalayan region is made up of five geological zones– the Sub-Himalayan Zone bound by
13200-508: The eastern Assam Himalayas. The Nepal Himalayas forms the centre of the Himalayan curve and extend for 800 km (500 mi) between the Kali and Teesta Rivers . The Great Himalayas in the region form the highest part of the entire Himalayas and consist of many of the eight-thousanders including Everest, Kanchenjunga at 8,586 m (28,169 ft), and Makalu at 8,463 m (27,766 ft). These mountains host large glaciers that form
13350-495: The ecosystem. At higher altitudes, Eastern and Western Himalayan subalpine conifer forests consisting of various conifers occur. Chir pine is the dominant species which occurs at elevations from 800–900 m (2,600–3,000 ft). Other species include Deodar cedar , which grows at altitudes of 1,900–2,700 m (6,200–8,900 ft), blue pine and morinda spruce between 2,200–3,000 m (7,200–9,800 ft). At higher altitudes, alpine shrubs and meadows occur above
13500-418: The essentially correct explanation in the 1840s, although it was several decades before it was fully accepted. The top 50 m (160 ft) of a glacier are rigid because they are under low pressure . This upper section is known as the fracture zone and moves mostly as a single unit over the plastic-flowing lower section. When a glacier moves through irregular terrain, cracks called crevasses develop in
13650-750: The experience of an American platoon operating in the Pech River Valley. The 2016 book Hammerhead Six: How Green Berets Waged an Unconventional War Against the Taliban to Win in Afghanistan's Deadly Pech Valley , by Ronald Fry with Tad Tuleja, depicts the experience of American Special Forces deployed there. This article related to a river in Afghanistan is a stub . You can help Misplaced Pages by expanding it . Glacier A glacier ( US : / ˈ ɡ l eɪ ʃ ər / ; UK : / ˈ ɡ l æ s i ər , ˈ ɡ l eɪ s i ər / )
13800-417: The flora and fauna of the region. Changes might decrease the territory available for local wildlife and reduction in prey for the predators . This puts the animals in conflict with humans as humans might encroach animal territories and the animals might venture into human habitats for search of food, which might exacerbate the economic loss of the local population. The Himalayan nations are signatories of
13950-521: The flora of the range. The increase in temperature has resulted in shifting of various species to higher elevations, and early flowering and fruiting. Many of the animal species are from the tropics, which have adapted to the various conditions across the Himalayan range. Some of the species of the Eastern Himalayas are similar to those found in East and South East Asia , while the animals of
14100-405: The formation of the Tibetan plateau . During miocene (20 mya), the increasing collision between the plates resulted in the top layer of metamorphic rocks getting peeled, which moved southwards to form nappes with trenches in between. As the mountains received rainfall, the waters flowing down the mountains eroded and steepened the southern slopes. The silt deposited by these rivers and streams in
14250-475: The fracture zone. Crevasses form because of differences in glacier velocity. If two rigid sections of a glacier move at different speeds or directions, shear forces cause them to break apart, opening a crevasse. Crevasses are seldom more than 46 m (150 ft) deep but, in some cases, can be at least 300 m (1,000 ft) deep. Beneath this point, the plasticity of the ice prevents the formation of cracks. Intersecting crevasses can create isolated peaks in
14400-448: The glacial base and facilitate sediment production and transport under the same moving speed and amount of ice. Material that becomes incorporated in a glacier is typically carried as far as the zone of ablation before being deposited. Glacial deposits are of two distinct types: Himalayas The Himalayas , or Himalaya ( / ˌ h ɪ m ə ˈ l eɪ . ə , h ɪ ˈ m ɑː l ə j ə / HIM -ə- LAY -ə, hih- MAH -lə-yə )
14550-453: The glacier to melt, creating a water source that is especially important for plants, animals and human uses when other sources may be scant. However, within high-altitude and Antarctic environments, the seasonal temperature difference is often not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, e.g., precipitation , mean temperature , and cloud cover , glacial mass changes are considered among
14700-428: The glacier will be accommodated by motion in the sediments, or if it'll be able to slide. A soft bed, with high porosity and low pore fluid pressure, allows the glacier to move by sediment sliding: the base of the glacier may even remain frozen to the bed, where the underlying sediment slips underneath it like a tube of toothpaste. A hard bed cannot deform in this way; therefore the only way for hard-based glaciers to move
14850-510: The glacier's surface area, more if the glacier calves icebergs. Ice in the accumulation zone is deep enough to exert a downward force that erodes underlying rock. After a glacier melts, it often leaves behind a bowl- or amphitheater-shaped depression that ranges in size from large basins like the Great Lakes to smaller mountain depressions known as cirques . The accumulation zone can be subdivided based on its melt conditions. The health of
15000-619: The ice at the bottom of the glacier move more slowly than ice at the top. In alpine glaciers, friction is also generated at the valley's sidewalls, which slows the edges relative to the center. Mean glacial speed varies greatly but is typically around 1 m (3 ft) per day. There may be no motion in stagnant areas; for example, in parts of Alaska, trees can establish themselves on surface sediment deposits. In other cases, glaciers can move as fast as 20–30 m (70–100 ft) per day, such as in Greenland's Jakobshavn Isbræ . Glacial speed
15150-420: The ice sheets of Antarctica and Greenland, has been estimated at 170,000 km . Glacial ice is the largest reservoir of fresh water on Earth, holding with ice sheets about 69 percent of the world's freshwater. Many glaciers from temperate , alpine and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause
15300-556: The ice to act as a lever that loosens the rock by lifting it. Thus, sediments of all sizes become part of the glacier's load. If a retreating glacier gains enough debris, it may become a rock glacier , like the Timpanogos Glacier in Utah. Abrasion occurs when the ice and its load of rock fragments slide over bedrock and function as sandpaper, smoothing and polishing the bedrock below. The pulverized rock this process produces
15450-488: The ice, called seracs . Crevasses can form in several different ways. Transverse crevasses are transverse to flow and form where steeper slopes cause a glacier to accelerate. Longitudinal crevasses form semi-parallel to flow where a glacier expands laterally. Marginal crevasses form near the edge of the glacier, caused by the reduction in speed caused by friction of the valley walls. Marginal crevasses are largely transverse to flow. Moving glacier ice can sometimes separate from
15600-411: The idea that meltwater, refreezing inside glaciers, caused the glacier to dilate and extend its length. As it became clear that glaciers behaved to some degree as if the ice were a viscous fluid, it was argued that "regelation", or the melting and refreezing of ice at a temperature lowered by the pressure on the ice inside the glacier, was what allowed the ice to deform and flow. James Forbes came up with
15750-418: The increased pressure can facilitate melting. Most importantly, τ D is increased. These factors will combine to accelerate the glacier. As friction increases with the square of velocity, faster motion will greatly increase frictional heating, with ensuing melting – which causes a positive feedback, increasing ice speed to a faster flow rate still: west Antarctic glaciers are known to reach velocities of up to
15900-423: The infrared OH stretching mode of the water molecule. (Liquid water appears blue for the same reason. The blue of glacier ice is sometimes misattributed to Rayleigh scattering of bubbles in the ice.) A glacier originates at a location called its glacier head and terminates at its glacier foot, snout, or terminus . Glaciers are broken into zones based on surface snowpack and melt conditions. The ablation zone
16050-456: The last ice age , and give rise to some of the world's major rivers such as the Indus , Ganges , and Tsangpo – Brahmaputra . Their combined drainage basin is home to nearly 600 million people including 52.8 million living in the vicinity of the Himalayas. The region is also home to many endorheic lakes. The Himalayas have a major impact on the climate of the Indian subcontinent. It blocks
16200-458: The livelihoods of the people in the Himalayas and the plains below. Despite its greater size, the Himalayas does not form a water divide across its span because of the multiple river systems that cut across the range. While the mountains were formed gradually, the rivers concurrently cut across deeper gorges ranging from 1,500–5,000 m (4,900–16,400 ft) in depth and 10–50 km (6.2–31.1 mi) in width. The actual water divide lies to
16350-590: The lower ranges on the southern slopes speak Indo-European languages. The inhabitants of the Western Himalayas include the Kashmiri people , who speak Kashmiri in the Vale of Kashmir and the Gujjar and Gaddi people , who speak Gujari and Gaddi respectively in the lower altitudes of Jammu and Himachal Pradesh in India. The last two are pastoral and nomadic people, who own flocks of cattle and migrate across
16500-468: The lowlands and grassland meadows in the mid altitudes. The composition and texture of the soils in the Himalayas also vary across regions. In the Eastern Himalayas , the wet soils has a high humus content conducive for growing tea . Podzolic soils occur in the eastern range of the Indus basin between the Indus and Shyok Rivers . The Ladakh region is generally dry with saline soil while fertile alluvial soils occur in select river valleys such as
16650-419: The main valley glaciers were 60–112 km (37–70 mi) long during the ice age. The glacier snowline (the altitude where accumulation and ablation of a glacier are balanced) was about 1,400–1,660 m (4,590–5,450 ft) lower than it is today. Thus, the climate would have been at least 7.0–8.3 °C (12.6–14.9 °F) colder than it is today. Since the late 20th century, scientists have reported
16800-477: The majority of the languages belonging to the first two categories. The Tibetan Himalayas are inhabited by Tibetan people , who speak Tibeto-Burman languages. The Great Himalayas are mostly inhabited by nomadic groups and tribes, with most of the population in Lesser Himalayas , and Shivalik Hills . People towards the Great Himalayas in the north parts mostly speak Tibeto-Burman, while populations in
16950-404: The margins. The mountains act as heat islands and heavier mountains absorb and retain more heat than the surroundings, and therefore influences the amount of heat needed to raise the temperature from the winter minimum to the summer maximum. However, soil temperatures mostly remain the same on both the sides of a mountain at altitudes higher than 4,500 m (14,800 ft). Temperatures in
17100-679: The most deformation. Velocity increases inward toward the center line and upward, as the amount of deformation decreases. The highest flow velocities are found at the surface, representing the sum of the velocities of all the layers below. Because ice can flow faster where it is thicker, the rate of glacier-induced erosion is directly proportional to the thickness of overlying ice. Consequently, pre-glacial low hollows will be deepened and pre-existing topography will be amplified by glacial action, while nunataks , which protrude above ice sheets, barely erode at all – erosion has been estimated as 5 m per 1.2 million years. This explains, for example,
17250-445: The most sensitive indicators of climate change and are a major source of variations in sea level . A large piece of compressed ice, or a glacier, appears blue , as large quantities of water appear blue , because water molecules absorb other colors more efficiently than blue. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing
17400-530: The north of the Himalayas with rivers flowing down both the sides of the mountains. Some of the major river systems and their drainage system outdate the formation of the mountains itself. The water divide is formed by the Karakoram and Hindu Kush ranges on the west and the Ladakh Range on the east, separating the Indus system from Central Asia. On the east, Kailas and Nyenchen Tanglha Mountains separate
17550-678: The northwest, which extend into Central Asia . Its western anchor Nanga Parbat lies south of the northernmost bend of the Indus river in Pakistan-administered Kashmir and its eastern anchor Namcha Barwa lies to the west of the great eastern bend of the Yarlung Tsangpo River in Tibet Autonomous Region of China . The Himalayas occupies an area of 595,000 km (230,000 sq mi) across six countries – Afghanistan , Bhutan , China, India , Nepal , and Pakistan . The sovereignty of
17700-436: The number of glacial lakes , some of which may be prone to dangerous floods. The region is expected to encounter continued increase in average annual temperature and 81% of the region's permafrost is projected to be lost by the end of the century. The increased warming and melting of snow is projected to accelerate the regional river flows until 2060 after which it would decline due to reduction in ice caps and glacier mass. As
17850-403: The ocean below, the difference in pressure creates a thermal low . The moist air from the ocean is pushed inwards towards the low pressure system causing the monsoon winds. It results in precipitation along the slopes due to the orographic effect as the air rises along the mountains and condenses. The monsoon begins at the end of May in the eastern fringes of the range and moves upwards towards
18000-477: The past half a century. The average warm days and nights had also increased by 1.2 days and 1.7 nights per decade while the average cold days and nights had declined by 0.5 and 1 respectively. This has also prolonged the length of the growing season by 4.25 days per decade. The climate change might results in erratic rainfall, varying temperatures, and natural disasters like landslides , and floods . The increasing glacier melt had been followed by an increase in
18150-725: The pooling of meltwater at the base of the glacier — perhaps delivered from a supraglacial lake — or the simple accumulation of mass beyond a critical "tipping point". Temporary rates up to 90 m (300 ft) per day have occurred when increased temperature or overlying pressure caused bottom ice to melt and water to accumulate beneath a glacier. In glaciated areas where the glacier moves faster than one km per year, glacial earthquakes occur. These are large scale earthquakes that have seismic magnitudes as high as 6.1. The number of glacial earthquakes in Greenland peaks every year in July, August, and September and increased rapidly in
18300-603: The precipitation is projected to increase concurrently, the annual river flows would be largely unaffected for the Eastern Himalayan rivers fed by monsoons, but would reduce the flows in the Western Himalayan rivers. Almost a billion people live on either side of the mountain and are prone to impact of the climate change. This includes the people who live in the mountains, who are more vulnerable due to temperature variations and other biota. Countries in
18450-410: The pressure of the layers of ice and snow above it, this granular ice fuses into denser firn. Over a period of years, layers of firn undergo further compaction and become glacial ice. Glacier ice is slightly more dense than ice formed from frozen water because glacier ice contains fewer trapped air bubbles. Glacial ice has a distinctive blue tint because it absorbs some red light due to an overtone of
18600-469: The range in the Kashmir region is disputed among India, Pakistan, and China. It is bordered by the Karakoram and Hindu Kush ranges on the northwest, Tibetan Plateau in the north, and by the Indo-Gangetic Plain in the south. Its western anchor Nanga Parbat lies south of the northernmost bend of the Indus river and its eastern anchor Namcha Barwa lies to the west of the great bend of
18750-462: The range in the Kashmir region is disputed amongst India, Pakistan, and China. The range varies in width from 350 km (220 mi) in the north-west to 150 km (93 mi) in the south-east. The range has several peaks exceeding an elevation of 8,000 m (26,000 ft) including Mount Everest , the highest mountain on Earth at 8,848 m (29,029 ft). The Himalayas consist of four parallel mountain ranges from south to north:
18900-1034: The region tropical and subtropical , temperate , coniferous , and grasslands . Tropical and subtropical broadleaf forests are mostly constricted to the high temperature and humid regions in Eastern and Central Himalayas , and pockets of Kashmir in the west. There are about 4,000 species of Angiosperms with major vegetation include Dipterocarpus , and Ceylon ironwood on porous soils at elevations below 2,400 m (7,900 ft) and oak , and Indian horse chestnut on lithosol between 1,100–1,700 m (3,600–5,600 ft). Himalayan subtropical pine forests with Himalayan screw pine trees occur above 4,000 m (13,000 ft) and Alder , and bamboo are found on terrains with higher gradient. Temperate forest occur at altitudes between 1,400–3,400 m (4,600–11,200 ft) while moving from south-east to north-west towards higher latitude. Eastern and Western Himalayan broadleaf forests consisting of sal trees dominate
19050-777: The region. More than 800 species of birds have been recorded with a large number of species restricted to the Eastern Himalayas. Amongst the bird species found include magpies such as black-rumped magpie and blue magpie , titmice , choughs , whistling thrushes , and redstarts . Raptors include bearded vulture , black-eared kite , and Himalayan griffon . Snow partridge and Cornish chough are found at altitudes above 5,700 m (18,700 ft). The Himalayan lakes also serve as breeding grounds for species such as black-necked crane and bar-headed goose . There are multiple species of reptiles including Japalura lizards, blind snakes , and insects such as butterflies . Several fresh water fish such as Glyptothorax are found in
19200-500: The region. As of 2022 , there are 575 protected areas established by the nations in the Himalayan-Hindu Kush region, which account for 40% of the land area and 8.5% of the global protected area. There are also four biodiversity hotspots , 12 ecoregions , 348 key biodiversity areas, and six UNESCO World Heritage Sites in the region. The Himalayan region with the associated Indo-Gangetic Plain and Tibetan plateau
19350-494: The same. The Himalayan region belongs to the Indomalayan realm . The flora and fauna of the Himalayas vary broadly across regions depending on the climate and geology. The Himalayas are home to multiple biodiversity hotspots, and is home to an estimated 35,000+ species of plants and 200+ species of animals. An average of 35 new species have been found every year since 1998. There are four types of vegetation found in
19500-593: The same. This has led to increased awareness on the impact of climate change, and adaptations such as change in crop cycles , introduction of drought resistant crops, and plantation of new trees. This has also led to the construction of more dams , canals , and other water structures, to prevent flooding and aid in agriculture. New plantations on barren lands to prevent landslides, and construction of fire lines made of litter and mud to prevent forest fires have been undertaken. However, lack of funding, awareness, access to technology, and government policy are barriers for
19650-567: The sea, often with an ice tongue , like Mertz Glacier . Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica, Baffin , Devon , and Ellesmere Islands in Canada, Southeast Alaska , and the Northern and Southern Patagonian Ice Fields . As the ice reaches the sea, pieces break off or calve, forming icebergs . Most tidewater glaciers calve above sea level, which often results in
19800-413: The slopes and the plains below. The effect of Himalayas on the hydroclimate impacts millions in the plains as the variability in monsoon rainfall is the main factor behind wet and dry years. As the Himalayas force the monsoon winds to give up most of the moisture before ascending up, the winds became dry once its reaches the north of the mountains. This results in the dry and windy cold desert climate in
19950-451: The slopes based on seasons. Various ethnic people such as Ladakhi , Balti , and Dard live on the north of the Great Himalayas along the Indus basin in the Kashmir and Ladakh regions spread across India, Pakistan, and China. The Dard speak Dard , which is part of Indo-European languages, while the Balti and Lakadkhi people speak Balti , and Ladakhi , which are part of Tibeto-Burman. In
20100-417: The snow-melt of the glaciers. The lower altitude lakes are replenished by a combination of rains, underground springs, and streams. Large lakes in the Himalayan basin were formed in the holocene period, when water pooled in the faults and the water supply was subsequently cut off. There are more than 4500 high altitude lakes of which about 12 large lakes contribute to more than 75% of the total lake area in
20250-409: The source of various rivers of the Ganges - Brahmaputra river system. The high altitude regions are uninhabitable with few mountain passes inbetween that serve as crossovers with the human settlements in the lower valleys. The Assam Himalaya forms the eastern most sub-section that extends eastward for 720 km (450 mi) from the Indian state of Sikkim through Bhutan and north-east India past
20400-409: The stagnant ice above, forming a bergschrund . Bergschrunds resemble crevasses but are singular features at a glacier's margins. Crevasses make travel over glaciers hazardous, especially when they are hidden by fragile snow bridges . Below the equilibrium line, glacial meltwater is concentrated in stream channels. Meltwater can pool in proglacial lakes on top of a glacier or descend into the depths of
20550-423: The stress being applied, ice will act as an elastic solid. Ice needs to be at least 30 m (98 ft) thick to even start flowing, but once its thickness exceeds about 50 m (160 ft) (160 ft), stress on the layer above will exceeds the inter-layer binding strength, and then it'll move faster than the layer below. This means that small amounts of stress can result in a large amount of strain, causing
20700-525: The summits of several peaks in the region such as Gangkhar Puensum , Machapuchare , and Kailash have been off-limits to climbers. The name of the range is derived from the Sanskrit word Himālay ( हिमालय ) meaning 'abode of snow'. It is a combination of the words him ( हिम ) meaning 'frost/cold' and ālay ( आलय ) meaning 'dwelling/house'. The name of the range is mentioned as Himavat ( Sanskrit : हिमवत्) in older literature such as
20850-584: The super-continent Gondwana broke up nearly 180 mya, the Indo-Australian plate slowly drifted northwards towards Eurasia for 130-140 million years. The Indian Plate broke up with the Australian Plate about 100 mya. The Tethys ocean constricted as the Indian plate moved gradually upward. As both the plates were made of continental crusts , which were less denser than oceanic crusts , the increased compressive forces resulted in folding of
21000-438: The surface snowpack may experience seasonal melting. A subpolar glacier includes both temperate and polar ice, depending on the depth beneath the surface and position along the length of the glacier. In a similar way, the thermal regime of a glacier is often described by its basal temperature. A cold-based glacier is below freezing at the ice-ground interface and is thus frozen to the underlying substrate. A warm-based glacier
21150-612: The trees. The Eastern Himalayan alpine shrub and meadows extend between 3,200–4,200 m (10,500–13,800 ft) and the Western Himalayan alpine shrub and meadows occur at altitudes of 3,600–4,500 m (11,800–14,800 ft). Major vegetation include Juniperus , Rhododendron on rocky terrain facing the Sun, various flowering plants at high elevations, and mosses , and lichens in humid, shaded areas. Interspersed Grasslands occur at certain regions, with thorns and semi-desert vegetation at low precipitation areas in
21300-592: The tropical zone to extend farther north in South Asia than anywhere else in the world. The temperatures are more pronounced in the Brahmaputra valley in the eastern section as it lies at a lower latitude and due to the latent heat of the forced air from the Bay of Bengal which condenses before moving past the Namcha Barwa , the eastern anchor of the Himalayas. Due to this, the permanent snow line
21450-543: The trough between the Himalayas and the Deccan plateau formed the Indo-Gangetic Plain . About 0.6 mya in the pleistocene period, the Himalayas rose higher and became the highest mountains on Earth. In the northern Great Himalayas , new gneiss and granite formations emerged on crystalline rocks that gave rise to the higher peaks. The summit of Mount Everest is made of unmetamorphosed marine ordovician limestone with fossil trilobites , crinoids , and ostracods from
21600-593: The underlying rock bed. The thrust faults created between the folds resulted in granite and basalt rocks from the Earth's mantle protruding through the crust . During the paleogene period (about 50 mya), the Indian plate collided with the Eurasian plate after it completely closed the Tethys ocean gap. The Indian plate continued to subduct under the Eurasian plate over the next 30 million years that resulted in
21750-417: The weight of the ice is supported by the underlying water, and the glacier is afloat. Glaciers may also move by basal sliding , where the base of the glacier is lubricated by the presence of liquid water, reducing basal shear stress and allowing the glacier to slide over the terrain on which it sits. Meltwater may be produced by pressure-induced melting, friction or geothermal heat . The more variable
21900-460: The west in June and July. There is heavy precipitation in the east which reduces progressively towards the west as the air becomes drier. Cherrapunji in Eastern Himalayas is one of the wettest places on Earth with an annual precipitation of 428 in (10,900 mm). The average annual rainfall varies from 120 in (3,000 mm) in the Eastern Himalayas to about 120 in (3,000 mm) in
22050-481: The world's tallest peaks, including Everest. It is mainly composed of granite rocks. The Tibetan Himalayas (also known as Tethys ) form the northern most sub-range of the Himalayas in Tibet . Longitudinally, the range is broadly divided into three regions– western , central , and eastern . The Western Himalayas form the westernmost section of the range and extend for about 560 km (350 mi) from
22200-524: The youngest mountain ranges on Earth and is made up of uplifted sedimentary and metamorphic rocks. It was formed more than 10 mya due to the subduction of the Indian tectonic plate with the Eurasian Plate along the convergent boundary . Due to the continuous movement of the Indian plate, the Himalayas keep rising every year, making them geologically and seismically active. The mountains consist of large glaciers , which are remnants of
22350-475: Was mentioned as Himmaleh in western literature such as Emily Dickinson 's poetry and Henry David Thoreau 's essays. The Himalayas run as an arc for 2,400 km (1,500 mi) from west-northwest to east-southeast at the northern end of the Indian subcontinent , separating the Indo-Gangetic Plains from the Tibetan Plateau . It is bordered by the Karakoram and Hindu Kush ranges on
22500-534: Was originally used to denote the 320 km (200 mi) stretch from Haridwar to the Beas River . The range is about 16 km (9.9 mi) wide on average and the elevation ranges from 900–1,200 m (3,000–3,900 ft). It rises along the Indo-Gangetic Plain and is often separated from the higher northern sub-ranges by valleys. The eastern portion of the range is called Churia Range in Nepal. The Lower or Lesser Himalaya (also known as Himachal )
#329670