The Himalayas have a profound effect on the climate of the Indian subcontinent and the Tibetan plateau. It prevents frigid, dry Arctic winds from blowing south into the subcontinent, which keeps South Asia much warmer than corresponding temperate regions in the other continents. It also forms a barrier for the monsoon winds, keeping them from traveling northwards, and causing heavy rainfall in the Terai region. The Himalayas are also believed to play an important part in the formation of Central Asian deserts such as the Taklamakan and Gobi deserts.
The mountain ranges also prevent western winter disturbances from Iran from traveling further, resulting in snow in Kashmir and rainfall for parts of Punjab and northern India. Despite being a barrier to the cold northerly winter winds, the Brahmaputra valley receives part of the frigid winds, thus lowering the temperature in the northeast Indian states and Bangladesh. These winds also cause the North East monsoon during this season for these parts.
In turn, the weather phenomenon called Jet Stream affects our image of the highest peaks on earth. The strong stream of winds from the west passes through Everest, creating a familiar plume of snows blowing from the summit, and visible from a great distance.
The Himalayas with dazzling pinnacles of snow-covered ranges extend for 2,250-km from the Namcha Barwa on the bend of the Tsang-po (Brahmaputra) to Nanga Parbat on the Indus. The range runs east to west up to central-Nepal and then takes a southeast to northwest direction. The average width of the Himalayas is about 200-km.
Compositions of the forests on this mighty ranges are affected by the combined effect of altitude, rainfall and latitude. The rainfall, mainly from the monsoons, decreases from the east to the west. Comparatively, in winter, due to the influence of tropical west wind drift, the northwest areas have more precipitation in the form of rain and snow. From these snow covered ranges with big glaciers, flow the great rivers that have made the Indo-Gangetic plain one of the most fertile in the world and the heart Land of India.
Beyond the Monsoon
Regions such as Ladakh & Zanskar that lie to the North of the main Himalayan range and escape the full impact of the monsoon. Humidity is always low in these regions, and receives only a few centimeters of rainfall a year. These regions also experience some of the coldest temperatures anywhere in the world, and it doesn’t get any warmer till the spring season in late April or early May.
In June, daytime temperatures frequently rise to the mid 200Cs, the snow on the passes melts and most of the treks can be undertaken from then on until the middle of October. Heavy rainstorms can occasionally be experienced in July and August, and River crossing should be undertaken with great care at this time. By September the conditions are ideal, and they normally remain so until late October even though nigh-time temperatures may fall below freezing. By November, the early winter snows fall on the passes closest to the Himalayas. In winter the villagers still travel, enduring the intense cold, to follow the valley floors where River crossings are no longer a problem.
After October the daytime temperatures drop, but the weather is generally settled until the middle of November when the first of the heavy winter snows fall on the high mountain passes. Winter months from December to March are often bleak. April and May are characterised by heavy precipitation, which falls as snow in the mountains, precluding trekking over the passes until the spring snows melt in June.
Most of the hill states of the West Himalayas including Kangra and Chamba, the Kullu valley, Shimla in Himachal and most regions of the Garhwal and Kumaon in Uttaranchal come under the influence of the Indian monsoon. Both Darjeeling and Sikkim are subject to the Indian monsoon that sweeps up from the Bay of Bengal, bringing heavy rainfall from early June until the end of September. The post-monsoon months of October and November provide settled conditions, with clear views of the mountains, although nighttime temperatures above 3,500m frequently fall below freezing.
Forest Cover – The Glory of the Himalayas
Because of the constant most of the Himalayan regions have a harsh environment therefore few animals and plants can survive over here. The few plants that do inhabit the Alpine consist of rhododendrons, the tea plant and shrub type plants. They have to adapt to the freezing temperatures, high winds and to a short growing season. That is why most of the plants grow low to the ground.
The Hindustan-Tibet road now called National Highway No. 22 takes one right across the Himalayas from the plains over forested mountain ranges along the Sutlej through the gorge in the great Himalayan range near Shipkila on the Indo-Tibet border. One of the most interesting and accessible areas are the forests on the ridge line that form the Indo Gangetic watershed on which lie Shimla, Narkanda and the most beautiful forests of silver Fir starting from Narkanda. Part of the Hindustan-Tibet road run along this watershed ridge.
From the plains to the snow clothed mountains, one goes through fine forests of Pine, Deodar, Fir, Oak, Rhododendron, Birch and finally between the tree line and the snows, rich alpine pastures. Inhabited areas, on cultivated terraced fields, can be seen women in their customary colourful clothes decorating the hillside like alpine blossoms.
The mountain fauna that are found in the Himalayan Alpine are similar to the mountain animals found in the surrounding areas of the Himalalayas. Some animals that have adapted the Himalayan climate include the mountain goat, which has a thick coat for warmth and strong hooves for running up the rocky slopes.
Climate of Himalayas
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 4880 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. It varies from The Tropical monsoon in south India to temperate in north India. India is such a vast country that the climate varies considerably. While the heat is unbearable in the Gangetic plain, the people of Ladakh shiver in the snowy cold.The Indian year passes through four seasons. Winter lasts from December to February, and summer from March to May.
The rainy season of Southwest monsoon is from June to September. The post monsoon season, which is North East monsoon in South India, is in October and November. The most pleasant weather in India lasts from June to November.There is a heavy rainfall in Northeastern region, the western slopes of the Western Ghats and parts of the Himalayas during the year. On the other hands, there is hardly any rainfall in Rajasthan, Kutch, and Laddakh. There is medium or average rainfall in other parts of the country.
Upland plain (Deccan Plateau) in south India, flat to rolling plain along the Ganges, deserts in western region of India, Himalayas in northern region. India is a vast country covering an area of 3,287,782 sq. km. The Himalayas, stretching from east to west in the north, form the northern boundary.The mighty mountain ranges separate India from China and Nepal. Where the Himalayan ranges end, there begin the great northern plains, are flat.