The Land

For a small country, Nepal has tremendous geographic diversity. It rises from less than 100 metres (328 ft) elevation in the tropical Terai—the northern rim of the Gangetic Plain, beyond the perpetual snow line to some 90 peaks over 7,000 metres (22,966 ft) including Earth's highest 8,848 metres (29,029 ft) Mount Everest or Sagarmatha. In addition to the continuum from tropical warmth to cold comparable to polar regions, average annual precipitation varies from as little as 160 millimetres (6.3 in) in the rainshadow north of the Himalaya to as much as 5,500 millimetres (216.5 in) on windward slopes. [1]
Along a south-to-north transect, Nepal can be divided into three belts: Terai, Hill and Mountain Regions. In the other direction it is divided into three major river systems, from east to west: Koshi, Gandaki/Narayani and Karnali (including the Mahakali/Sarda along the western border), all tributaries of the Ganges. The Ganges-Yarlung Zangbo/Brahmaputra watershed largely coincides with the Nepal-Tibet border, however several Ganges tributaries rise inside Tibet