Geographical Location of District Lahaul Spiti
In terms of area, Lahaul Spiti is the largest district of Himachal Pradesh. Its total area is 13,833 sq km. The district shares an international border with Tibet to the east, Ladakh to the north, and the district of Chamba to the northeast. It also borders Kangra and Kullu to the south and Kinnaur to the southwest. (see more detail https://hplahaulspiti.nic.in/history/)
Physiographic Description of District Lahaul Spiti
Lahaul Spiti can be divided into two physiographic divisions: Lahaul and Spiti.A high mountain crest known as the Kunzum Range separates Spiti from Lahaul. Lahaul is entirely located in the Greater Himalayas, whereas the physiography of Spiti is a transition zone into the Zanskar Range. The altitude of Spiti is slightly higher than Lahaul. This difference in physiography is quite visible in vegetation covers and underlying rocks. In Lahaul, one can easily find grass, shrubs, and trees, but Spiti is a complete desert, devoid of all kinds of dense vegetation.
Important Mountain Ranges of Lahaul Spiti
The entire district is located in the main Himalayan zone; its altitude never decreases below 2,300 meters. The South Tibetan Detachment, a geological fault that separates the Greater Himalayan crystalline rocks from Tibetan sedimentary rocks, passes through the district. Pir Panjal, Greater Himalaya, and Zanskar are the important ranges of the district.( see the 3d Physiographic map here Complete Physiographic Division of Himachal Pradesh.)
Zanskar Range: The Zanskar Range touches the district on the border with Tibet. Like the Greater Himalayas, it is also a high mountain range; in fact, it is part of the Greater Himalayas. Parallel to the Great Himalaya, but geologically part of the Trans-Himalayas. Zanskar range forms the backdrop of Spiti tehsil, where barren ridges dominate the horizon. Zanskar range characterized by distinct climate and physiography, closer in nature to Tibet than to the Indian Himalaya.
Pir Panjal Range: This (Lesser Himalayan) range enters Lahaul from the east, where it forms a natural boundary with Chamba. On its further eastern side, it separates the district from Kullu, and thereafter it gradually merges with the Greater Himalayas. It also delineates the Chandrabhaga water basin from the Beas basin. The famous Rohtang Pass is located on this range, connecting the Kullu valley with the Lahaul valley. Some peaks exceed 6,000 meters, such as Dara Goh, Khodo Goh, and Makar-Beh.
Greater Himalayan Range: This is the principal range of the district. It enters the district from the northwest and continues toward the east, where a section of it is called the Kunzum Range. The famous Kunzum Pass, located on this range, connects the Lahaul and Spiti valleys. The Greater Himalayas also act as a giant wall beyond which the Indian Monsoon cannot penetrate.
Valleys of Lahaul Spiti
Lahaul has many famous valleys, such as Chandra (also known as Rangoli), Bhaga (also known as Gara), Miyar Valley, and Chandrabhaga Valley (also known as Pattan Valley). Andrew Wilson, a European traveler (1873), called the Lahaul valley “a valley of glaciers.” Spiti Valley, Pin, and Paraichu Valleys are the important valleys of the Spiti Division.
Drainage Sytem of Lahaul Spiti
The Paraichu/Parang Valley is located in the inner ridges of the Zanskar range and is separated from the main Spiti Valley by a mountain ridge. This is a rugged zone of mountains. The Parang River, after originating in Spiti, flows into Tibet and rejoins the Spiti River at Sumdo on the Indo-Tibet border. Lahaul Spiti has typical cold desert features; these geomorphological features are shaped by extreme climatic conditions, minimal precipitation, and processes such as wind and glacial activity. (See more detail Chandrabhaga River ,Himachal Pradesh, a Holistic Study.)
Glacier Land Forms of Lahaul Spiti
By and large, glaciers are the single largest force in shaping the regional landscape. U-shaped hanging valleys created by glacier erosion dominate the overall landscape of the region. Chandra, Bhaga, Miyar, Spiti, Lingti, and Pin are a few important valleys.The district also has various glacier-moraine-dammed lakes, such as Suraj Tal and Chandratal . These lakes occasionally cause havoc.( see more detail map of Glacier:- Glacier)
Cirques, which are bowl-shaped depressions carved by glacier activity and often hosting small lakes called tarns, are also found in high-mountain reaches. Apart from these, wind-eroded rock structures, sandy plains, and sparse vegetation dominate the regional landscape. (see more glacier landforms https://www.pmfias.com/glacial-landforms-erosional-depositional-cirque-arete-fjord-esker-drumlin-moraine/)
