Himalayas, also Himalaya (Sanskrit for “abode of snow”), mountain system in Asia, forming a broad continuous arc for nearly 2,600 km (1,600 mi) along the northern fringes of the Indian subcontinent, from the bend of the Indus River in the northwest to the Brahmaputra River in the east. The Himalayas range, averaging 320 to 400 km (200 to 250 mi) in width, rises sharply from the Gangetic Plain. North of this mountain belt lies the Tibetan Plateau (Qing Zang Gaoyuan). The Himalayas form the earth’s highest mountain region, containing 9 of the 10 highest peaks in the world. Among these peaks are the world’s highest mountain, Mount Everest (8,850 m/29,035 ft), which is on the Nepal-Tibet border; the second highest peak, K2 or Mount Godwin Austen (8,611 m/28,251 ft), located on the border between China and Jammu and Kashmīr, a territory claimed by India and Pakistan; the third highest peak, Kānchenjunga (8,598 m/28,209 ft) on the Nepal-India border; Makālu (8,481 m/27,824 ft) on the Nepal-Tibet border; Dhaulāgiri (8,172 m/26,811 ft) and Annapūrna 1 (8,091 m/26,545 ft) in Nepal; Nanga Parbat (8,125 m/26,657 ft) in the Pakistani-controlled portion of Jammu and Kashmīr; and Nanda Devi (7817 m/25,645 ft) in India.
GEOLOGIC FORMATION AND STRUCTURE
The Himalayan mountain system developed in a series of stages 30 to 50 million years ago. The Himalayan range was created from powerful earth movements that occurred as the Indian plate pressed against the Eurasian continental plate (see Plate Tectonics). The earth movements raised the deposits laid down in the ancient, shallow Tethys Sea (on the present site of the mountains) to form the Himalayan ranges from Pakistan eastward across northern India, and from Nepal and Bhutan to the Myanmar (Burmese) border. Even today the mountains continue to develop and change, and earthquakes and tremors are frequent in the area.
TOPOGRAPHY
Physically, the Himalayas forms three parallel zones: the Great Himalayas, the Middle Himalayas (also known as the Inner or Lesser Himalayas), and the Sub-Himalayas, which includes the Siwālik Range and foothills and the Tarāi and Duars piedmont (an area of land formed or lying at the foot of a mountain or mountain range). Each of these lateral divisions exhibit certain similar topographic features. The Great Himalayas, the highest zone, consists of a huge line of snowy peaks with an average height exceeding 6,100 m (20,000 ft). The width of this zone, composed largely but not entirely of gneiss and granite, is about 24 km (about 15 mi). Spurs from the Great Himalayas project southwards into the Middle Himalayas in an irregular fashion. The Nepal and Sikkim (a state of northern India) portion of the Great Himalayas contains the greatest number of high peaks. The snow line on the southern slopes of the Great Himalayas varies from 4,480 m (14,700 ft) in the eastern and central Himalayas of Nepal and Sikkim to 5,180 m (17,000 ft) in the western Himalayas. To the north of the Great Himalayas are several ranges such as the Zāskār, Ladakh, and the Kailas. The Karakoram Range lies on the Tibetan side of the Great Himalayas.
The Great Himalayan region is one of the few remaining isolated and inaccessible areas in the world today. Some high valleys in the Great Himalayas are occupied by small clustered settlements. Extremely cold winters and a short growing season limit the farmers to one crop per year, most commonly potatoes or barley. The formidable mountains have limited the development of large-scale trade and commerce despite the construction of highways across the mountains linking Nepal and Pakistan to China. Older trails, which cross the mountains at high passes, also have limited trade and are open only during the summer months.
The Middle Himalayas range, which has a width of about 80 km (about 50 mi), borders the Great Himalayan range on the south. It consists principally of high ranges both within and outside of the Great Himalayan range. Some of the ranges of the Middle Himalayas are the Nāg Tibba, the Dhaola Dhār, the Pīr Panjāl, and the Mahābhārat. The Middle Himalayas possess a remarkable uniformity of height; most are between 1,830 and 3,050 m (between 6000 and 10,000 ft).
The Middle Himalayas region is a complex mosaic of forest-covered ranges and fertile valleys. While not as forbidding as the Great Himalayas to the north, this range has nonetheless served to isolate the valleys of the Himalayas from the plains of the Indus and Ganges rivers in Pakistan and northern India. Except for the major valley centers such as Srīnagar, Kāngra, and Kathmandu, and hill towns such as Simla, Mussoorie, and Dārjiling (Darjeeling), the region is moderately populated. Within the Middle Himalayas the intervening mountain ranges tend to separate the densely populated valleys. The numerous gorges and rugged mountains make surface travel difficult in any direction. Few roads or transport routes exist between towns, partly because it is expensive to build them over the high, rough terrain. Only major population centers are linked by air and roads with principal cities in India and Pakistan.
The Sub-Himalayas, which is the southernmost and the lowest zone, borders the plains of North India and Pakistan. It comprises the Siwālik Range and foothills as well as the narrow piedmont plain at the base of the mountains. The width of the Sub-Himalayas gradually narrows from about 48 km (about 30 mi) in the west until it nearly disappears in Bhutan and eastern India. A characteristic feature of the Sub-Himalayas is the large number of long, flat-bottomed valleys known as duns, which are usually spindle-shaped and filled with gravelly alluvium. South of the foothills lies the Tarāi and Duars plains. The southern part of the Tarāi and Duars plains is heavily farmed. The northern part was forest inhabited by wild animals until about the 1950s. Most of the forests of this region have been destroyed, and much of the land has been reclaimed for agriculture.
The Middle Himalayas range, which has a width of about 80 km (about 50 mi), borders the Great Himalayan range on the south. It consists principally of high ranges both within and outside of the Great Himalayan range. Some of the ranges of the Middle Himalayas are the Nāg Tibba, the Dhaola Dhār, the Pīr Panjāl, and the Mahābhārat. The Middle Himalayas possess a remarkable uniformity of height; most are between 1,830 and 3,050 m (between 6000 and 10,000 ft).
The Middle Himalayas region is a complex mosaic of forest-covered ranges and fertile valleys. While not as forbidding as the Great Himalayas to the north, this range has nonetheless served to isolate the valleys of the Himalayas from the plains of the Indus and Ganges rivers in Pakistan and northern India. Except for the major valley centers such as Srīnagar, Kāngra, and Kathmandu, and hill towns such as Simla, Mussoorie, and Dārjiling (Darjeeling), the region is moderately populated. Within the Middle Himalayas the intervening mountain ranges tend to separate the densely populated valleys. The numerous gorges and rugged mountains make surface travel difficult in any direction. Few roads or transport routes exist between towns, partly because it is expensive to build them over the high, rough terrain. Only major population centers are linked by air and roads with principal cities in India and Pakistan.
The Sub-Himalayas, which is the southernmost and the lowest zone, borders the plains of North India and Pakistan. It comprises the Siwālik Range and foothills as well as the narrow piedmont plain at the base of the mountains. The width of the Sub-Himalayas gradually narrows from about 48 km (about 30 mi) in the west until it nearly disappears in Bhutan and eastern India. A characteristic feature of the Sub-Himalayas is the large number of long, flat-bottomed valleys known as duns, which are usually spindle-shaped and filled with gravelly alluvium. South of the foothills lies the Tarāi and Duars plains. The southern part of the Tarāi and Duars plains is heavily farmed. The northern part was forest inhabited by wild animals until about the 1950s. Most of the forests of this region have been destroyed, and much of the land has been reclaimed for agriculture.
The Great Himalayan region is one of the few remaining isolated and inaccessible areas in the world today. Some high valleys in the Great Himalayas are occupied by small clustered settlements. Extremely cold winters and a short growing season limit the farmers to one crop per year, most commonly potatoes or barley. The formidable mountains have limited the development of large-scale trade and commerce despite the construction of highways across the mountains linking Nepal and Pakistan to China. Older trails, which cross the mountains at high passes, also have limited trade and are open only during the summer months.
The Middle Himalayas range, which has a width of about 80 km (about 50 mi), borders the Great Himalayan range on the south. It consists principally of high ranges both within and outside of the Great Himalayan range. Some of the ranges of the Middle Himalayas are the Nāg Tibba, the Dhaola Dhār, the Pīr Panjāl, and the Mahābhārat. The Middle Himalayas possess a remarkable uniformity of height; most are between 1,830 and 3,050 m (between 6000 and 10,000 ft).
The Middle Himalayas region is a complex mosaic of forest-covered ranges and fertile valleys. While not as forbidding as the Great Himalayas to the north, this range has nonetheless served to isolate the valleys of the Himalayas from the plains of the Indus and Ganges rivers in Pakistan and northern India. Except for the major valley centers such as Srīnagar, Kāngra, and Kathmandu, and hill towns such as Simla, Mussoorie, and Dārjiling (Darjeeling), the region is moderately populated. Within the Middle Himalayas the intervening mountain ranges tend to separate the densely populated valleys. The numerous gorges and rugged mountains make surface travel difficult in any direction. Few roads or transport routes exist between towns, partly because it is expensive to build them over the high, rough terrain. Only major population centers are linked by air and roads with principal cities in India and Pakistan.
The Sub-Himalayas, which is the southernmost and the lowest zone, borders the plains of North India and Pakistan. It comprises the Siwālik Range and foothills as well as the narrow piedmont plain at the base of the mountains. The width of the Sub-Himalayas gradually narrows from about 48 km (about 30 mi) in the west until it nearly disappears in Bhutan and eastern India. A characteristic feature of the Sub-Himalayas is the large number of long, flat-bottomed valleys known as duns, which are usually spindle-shaped and filled with gravelly alluvium. South of the foothills lies the Tarāi and Duars plains. The southern part of the Tarāi and Duars plains is heavily farmed. The northern part was forest inhabited by wild animals until about the 1950s. Most of the forests of this region have been destroyed, and much of the land has been reclaimed for agriculture.
The Middle Himalayas range, which has a width of about 80 km (about 50 mi), borders the Great Himalayan range on the south. It consists principally of high ranges both within and outside of the Great Himalayan range. Some of the ranges of the Middle Himalayas are the Nāg Tibba, the Dhaola Dhār, the Pīr Panjāl, and the Mahābhārat. The Middle Himalayas possess a remarkable uniformity of height; most are between 1,830 and 3,050 m (between 6000 and 10,000 ft).
The Middle Himalayas region is a complex mosaic of forest-covered ranges and fertile valleys. While not as forbidding as the Great Himalayas to the north, this range has nonetheless served to isolate the valleys of the Himalayas from the plains of the Indus and Ganges rivers in Pakistan and northern India. Except for the major valley centers such as Srīnagar, Kāngra, and Kathmandu, and hill towns such as Simla, Mussoorie, and Dārjiling (Darjeeling), the region is moderately populated. Within the Middle Himalayas the intervening mountain ranges tend to separate the densely populated valleys. The numerous gorges and rugged mountains make surface travel difficult in any direction. Few roads or transport routes exist between towns, partly because it is expensive to build them over the high, rough terrain. Only major population centers are linked by air and roads with principal cities in India and Pakistan.
The Sub-Himalayas, which is the southernmost and the lowest zone, borders the plains of North India and Pakistan. It comprises the Siwālik Range and foothills as well as the narrow piedmont plain at the base of the mountains. The width of the Sub-Himalayas gradually narrows from about 48 km (about 30 mi) in the west until it nearly disappears in Bhutan and eastern India. A characteristic feature of the Sub-Himalayas is the large number of long, flat-bottomed valleys known as duns, which are usually spindle-shaped and filled with gravelly alluvium. South of the foothills lies the Tarāi and Duars plains. The southern part of the Tarāi and Duars plains is heavily farmed. The northern part was forest inhabited by wild animals until about the 1950s. Most of the forests of this region have been destroyed, and much of the land has been reclaimed for agriculture.
CLIMATE
The Himalayas influences the climate of the Indian subcontinent by sheltering it from the cold air mass of Central Asia. The range also exerts a major influence on monsoon and rainfall patterns. Within the Himalayas climate varies depending on elevation and location. Climate ranges from subtropical in the southern foothills, with average summer temperatures of about 30° C (about 86° F) and average winter temperatures of about 18° C (about 64° F); warm temperate conditions in the Middle Himalayan valleys, with average summer temperatures of about 25° C (about 77° F) and cooler winters; cool temperate conditions in the higher parts of the Middle Himalayas, where average summer temperatures are 15 to 18° C (59 to 64° F) and winters are below freezing; to a cold alpine climate at higher elevations, where summers are cool and winters are severe. At elevations above 4,880 m (16,000 ft) the climate is very cold with below freezing temperatures and the area is permanently covered with snow and ice. The eastern part of the Himalayas receives heavy rainfall; the western part is drier.
The Himalayas influences the climate of the Indian subcontinent by sheltering it from the cold air mass of Central Asia. The range also exerts a major influence on monsoon and rainfall patterns. Within the Himalayas climate varies depending on elevation and location. Climate ranges from subtropical in the southern foothills, with average summer temperatures of about 30° C (about 86° F) and average winter temperatures of about 18° C (about 64° F); warm temperate conditions in the Middle Himalayan valleys, with average summer temperatures of about 25° C (about 77° F) and cooler winters; cool temperate conditions in the higher parts of the Middle Himalayas, where average summer temperatures are 15 to 18° C (59 to 64° F) and winters are below freezing; to a cold alpine climate at higher elevations, where summers are cool and winters are severe. At elevations above 4,880 m (16,000 ft) the climate is very cold with below freezing temperatures and the area is permanently covered with snow and ice. The eastern part of the Himalayas receives heavy rainfall; the western part is drier.
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