2. The Trans-Himalaya Ranges
3. The Eastern Hills.
The Himalaya Ranges:
The Himalayas are a series of several more or less parallel ranges separated by deep valleys. The mountain ranges have steep slope towards the south and a much gentler slope towards the north. Longitudinally there are at least three parallel ranges. They are:
1. The Greater Himalaya,
2. The Middle or the Lesser Himalaya, and
3. The Shiwalik Ranges.
The Greater Himalaya is the northernmost range and is also known as Himadri. Its average height is more than 6000 metres above the sea level. This is the highest and the most continuous mountain range in the world. This range ends abruptly in Nanga Parbat in the northwest and in the Namcha Barwa in the northeast. Snow-capped peaks over 8000 metres above the sea level are found in this range.
The Mount Everest, also called Sagarmatha or Chomo Langma (8848 metres high) on the Nepal- China border, is the highest mountain peak in the world. Kanchenjunga (8598 metres high) is the highest peak in the Indian Himalayas.
The Himadri cannot be easily crossed as the passes are higher than 4500 metres above the sea level. They are snowbound for a major part of the year. The Zoji La in Jammu and Kashmir, the Bara Lacha La and the Shipki La in Himachal Pradesh, the Niti pass in Uttarakhand, the Nathu La and the Jelep La in Sikkim, Bomdi La in Arunachal Pradesh are some of the important passes in the Great Himalayas.
The Middle or the Lesser Himalaya is also called the Himachal. It is located towards the south of the Great Himalayas. The average height above the mean sea level varies between 3500 metres and 4500 metres. Most of the peaks are more than 5000 metres high and are covered with snow throughout the year. The important mountain ranges in this region include the Pir Panjal, the Dhaola Dhar, the Mussoorie Range and the Nag Tibba.
The Pir Panjal range in Kashmir extends from the Jhelum River for a distance of about 300 km to 400 km. It is the longest range and is separated from the Zaskar range by the Vale of Kashmir. The main passes are the Pir Panjal Pass and the Banihal Pass used by the Jammu-Srinagar highway. Further east lies the Mussoorie and the Nag Tibba ranges.
The Vale of Kashmir lies between the Pir Panjal and the Zaskar ranges. It is about 135 km long and about 40 km wide in the centre. The average height is about 1585 m above the mean sea level. The Jhelum River meanders through this area before crossing the Pir Panjal range. The important hill stations like Shimla, Mussoorie, Ranikhet, Naini Tal, Almora, Darjiling, etc., are located in the Middle Himalayas.
The Shiwalik Ranges run almost parallel to the Lesser Himalayas for a distance of about 2400 km from the Potwar Plateau in the west to the Brahmaputra valley in the east. Its width varies from about 50 km in Himachal Pradesh to less than 15 km in Arunachal Pradesh.
The height varies from 600 metres to 1500 metres above the sea level. The Shiwalik ranges are formed of sand and gravel, which have been brought and deposited by the Himalayan Rivers. The Shiwalik ranges are known by different names in different areas.
The Shiwalik ranges were formed after the formation of the Himalayas. They obstructed the courses of the rivers and formed temporary lakes. The rivers deposited their sediments in these lakes.
After sometime the lakes were drained away leaving behind plains called Duns. Dehra Dun is the best example. The southern slopes of the Shiwalik Ranges in Punjab and Himachal Pradesh are highly dissected by several seasonal streams, locally called Chos.
The Trans-Himalayan Ranges:
The Zaskar, the Ladakh and the Karakoram are some of the important mountain ranges in the Trans- Himalayan system. These are located towards the north of the Great Himalayan Mountains. These mountain ranges extend in the east-west direction for a distance of about 1000 km. Their average height is about 3000 metres above the sea level.
The Zaskar range runs parallel to the Great Himalayan range. The Ladakh range is located towards the north of the Zaskar range and runs parallel to it. This range is about 300 km long and the average height is about 5800 metres above the mean sea level.
The Karakoram is the northernmost mountain range in the Trans-Himalayan system. It forms the frontier of India with Afghanistan and China. It also acts as a water-shed between India and Turkmenistan. The Karakoram Range extends eastwards from the Pamir Knot for a distance of about 800 km.
It has many lofty mountain peaks and is home to some of the biggest glaciers of the world outside the polar region. K2 (Mount Godwin Austin) is the highest peak in the Karakoram Range and is about 8611 metres high. It is the highest mountain peak of India and the second highest peak in the world.
The Ladakh Plateau, the highest in India, is located towards the northeast of the Karakoram Range. The average elevation of the plateau is about 5000 metres above the mean sea level.
The Eastern Hills:
In the eastern part of India, the Himalaya Mountains turn southwards and form a series of low hills, which are collectively called the Purvachal. The eastern hills extend from Arunachal Pradesh in the north to Mizoram in the south. Some of these hills form the international boundary between India and Myanmar.
In the north lies the Patkai Bum. The elevation varies from about 2000 metres to 3000 metres. Towards the south, the Patkai Bum merges with the Naga Hills.
They together act as the water-shed between India and Myanmar. Further southwards are the Manipur Hills, which extend into the Mizo Hills.
Towards the west of this chain of hills and along the border of Bangladesh lies the Meghalaya plateau. The Garo, Khasi and Jaintia Hills are the important hill ranges located in this plateau that forms the eastern hills. The elevation of the eastern hills decreases from north to south. The eastern hills have rough terrain, dense forests and swift flowing streams.