Why are the Himalayas so cold?

 Introduction 

You can mistakenly believe that the climate is constant throughout the entire Himalayan mountain range if you haven't personally experienced them. But nothing could be further from the truth than this idea. Understanding the seasonal weather variations that occur in various sections of the Himalayas is essential if you're thinking about visiting this area. The Indian monsoon exerts the greatest influence on climate, therefore whether it occurs or not has a significant impact on weather predictions. To predict the various meteorological conditions that define the Himalayan terrain, it is crucial to comprehend the subtleties of the monsoon's influence.

A wind system that experiences seasonal reversal is what is known as a monsoon. According to the theory behind this phenomena, when the Earth's surface is heated by the sun during the summer, the atmosphere rises and draws humid air from the ocean. Conversely, this process reverses as the sun's heating decreases in the winter, resulting in the predominance of a more arid and falling air mass. Early in June, the monsoon begins to influence places like far eastern India, Bhutan, and Nepal, and it stays there for a long time. As a result, the western Himalayas have significantly drier weather than their eastern counterparts, and the monsoon comes later in the year.

In context of Nepal, the two main trekking seasons in Nepal are from late September through early November and from March through May. Due to their high elevations, the Everest and Annapurna regions both see substantial winter snowfall, allowing for trekking options from December to February (Refer to - Everest's Weather). The northern Himalayas, which include regions like Mustang and Dolpo, are partially in a rain shadow, which results in less monsoon moisture. These aforementioned areas stand out as the best options for trekkers contemplating Nepal in July and August.

The Himalayas, also known as the Nepali Himalaya, are a massive mountain range in Asia that naturally separates the southern alluvial plains of the Indian subcontinent from the northern Tibetan Plateau. The highest peaks on Earth are found inside this mountain chain, which has over 110 summits that rise above 24,000 feet (7,300 meters) above sea level. Mount Everest, also known as Chomolungma in Tibetan, Qomolangma Feng in Chinese, and Sagarmatha in Nepali, is one of these peaks and is the highest point in the world, rising to a lofty elevation of 29,032 feet (8,849 meters).

The mountain ranges are essential parts of a vast mountain chain that extends from North Africa to the coast of Southeast Asia along the Pacific Ocean, defining the northern boundary of the Indian subcontinent and acting as a formidable barrier between it and the territories to the north. The Himalayan range itself stretches continuously for about 1,550 miles (2,500 km) in an east-west direction, from Namjagbarwa (also known as Namcha Barwa) Peak in China's Tibet Autonomous Region to Nanga Parbat, which rises to a height of 25,445 feet (7,756 meters) in Pakistan's portion of Kashmir. The countries of Nepal and Bhutan lie tucked between these antagonistic western and eastern points. The Himalayas are bordered to the northwest by the mountain ranges of the Hindu Kush and Karakoram, and to the north by Tibet's vast, high Plateau. The Himalayas, which stretch from south to north, range in width from 125 to 250 miles (200 to 400 km). The total area of the Himalayan ranges to about 230,000 square miles (595,000 square kilometers).

Physical characteristics, historical geology and Himalayan Physiography determined the coldness of the Himalayas which described detail in following:

 

The Himalayas are known for their lofty altitudes, sharp-edged and steep-sided peaks, wide valleys and alpine glaciers, topography intricately carved by erosion, seemingly impenetrable river gorges, complex geological formation, and a succession of elevational belts (or zones) that exhibit distinct ecological associations with regard to plant and animal life as well as climate. The Himalayas appear to be a massive crescent with the main axis reaching above the snow line when viewed from the south. The lower-valley glaciers in this elevated area are nourished by snowfields, alpine glaciers, and the occurrence of avalanches, which eventually become the sources of the bulk of Himalayan rivers. The Himalayas do, however, cover a sizable area below the snow line. The ongoing process of mountain-building that shaped this range remains active, resulting in the uplift of bedrock alongside substantial stream erosion and the occurrence of massive landslides.

Four parallel longitudinal belts with varying widths that make up the Himalayan mountain ranges, each with distinctive physical traits and a distinctive geological evolution, can be used to classify them. The Greater Himalaya Range, also known as the Great Himalayas, the Lesser or Lower Himalayas, the Outer or Sub-Himalayas, and the Tethys or Tibetan Himalayas are the names of these belts. The Siwalik Range is another name for this range. Further north within Tibet proper, past them, are the Trans-Himalayas. The western, central, and eastern sectors make up the three main mountainous sections of the Himalayas when seen from the west to the east.

During a span of 65 million years, significant plate-tectonic forces on a global scale have orchestrated the movement of the Earth's crust, orchestrating the creation of a belt of Eurasian mountain ranges. This expansive belt, encompassing the Himalayas among other ranges, extends from the Alps in the west to the mountains of Southeast Asia in the east.

Himalayan PhysiographyThe Tethys Ocean, which surrounded the entirety of the southern edge of the Eurasian landmass, with the exception of the Arabian Peninsula and the Indian subcontinent, was created during the Jurassic Period, from 201 to 145 million years ago, as a result of a dramatic downward warping of the Earth's crust. Gondwana, an extinct supercontinent, started to break up around 180 million years ago. One piece of Gondwana, which contained the Indian subcontinent within its lithospheric plate, set out on a northward track, which over the following 130 to 140 million years led to a collision path with the Eurasian Plate. The Tethys trench was meticulously restricted between the Indian-Australian Plate and the Eurasian Plate by the Indian-Australian Plate, acting like a massive pincer.

Increased compressive pressures caused by the Tethys trench's steady narrowing bent the rock strata below it, creating a web of interconnected faults in its marine deposits. Massive intrusive masses of granite and basalt penetrated the weakened sedimentary crust as they emerged from the mantle's depths. The Indian subcontinent and Eurasia eventually collided between 40 and 50 million years ago. India's plate was sheared or subducted southward beneath the Tethys trench, steepening its angle of fall through time.

As the Indian-Australian Plate slid downward over a period of around 30 million years, the Tethys Ocean gradually drained, giving rise to the Tibetan Plateau. As a climatic barrier, the Trans-Himalayan ranges eroded southern rivers and altered Asia's drainage patterns. The Indus, Ganges, and Brahmaputra rivers caused a buildup of sediment in the Arabian Sea and Bay of Bengal. The Himalayan mountains were first formed by the collision of the Indian subcontinental plate and the old Tethys trench some 20 million years ago. During this process, Gondwana rocks were shoved southward and eroded material was transported to the plains by rivers that were downcutting. Within the last 600,000 years, there has been a significant uplift, with crystalline materials helping to construct the Himalayan peaks. The Great Himalayas developed as a climatic barrier that changed the landscape by shifting river courses. Minor rivers were diverted through structural flaws while transverse rivers continued their downcutting. The majestic Himalayas and the area around them have been created over millions of years by the intricate geological and tectonic processes.

The Siwalik Range, which encircles the southernmost portion of the Himalayan mountain chain, is part of the Outer Himalayas, along with flat lowlands. In Himachal Pradesh, the Siwaliks are a stretch of the Himalayas that is around 62 miles (100 km) wide. At an altitude of 900 feet (275 meters), its southern edge rises 2,500 feet (760 meters) northward. The Siwalik Range descends precipitously to flat basins or duns like Dehra Dun and the Indian plains.The Lesser Himalayas, which are next to the Siwaliks, are 50 miles (80 km) wide, with valleys that are 3,000 feet (900 meters) deep and peaks that reach heights of 15,000 feet (4,500 meters). The Greater Himalayas split out into the Nag Tibba, Dhaola Dhar, and Pir Panjal ranges farther north. Near Nepal, the easternmost divides the Ganges and Yamuna watersheds at a height of about 26,800 feet (8,200 meters), the Nag Tibba.

The Lesser Himalayas are located to the west and include the Vale of Kashmir in the Jammu and Kashmir union region. The basin is approximately 50 miles (80 km) wide, 100 miles (160 km) long, and has a height of 5,100 feet (1,600 meters) on average. Wular Lake is traversed by the meandering Jhelum River.

Ten of the world's tallest peaks—the Great Himalaya Range, which forms the dominating spine—rise above 26,250 feet (8,000 meters) in Nepal. From Jammu and Kashmir to Sikkim, it runs in a northwest-southeast direction before turning east-west for 260 miles (420 km) via Bhutan and Arunachal Pradesh before curving northeast to Namcha Barwa. The Spiti Basin and Zaskar Range in Kashmir and Himachal Pradesh, which stretch into Tibet, blur the boundary between the northern and southern regions.