Bailey–Morshead exploration of Tsangpo Gorge

The Bailey–Morshead exploration of the Tsangpo Gorge was an unauthorised expedition by Frederick Bailey and Henry Morshead in 1913 which for the first time established the definite route by which the Tsangpo River reaches the sea from north of Himalaya.

North of Himalaya, the Yarlung Tsangpo River flows east through the Tibetan Plateau and then turns south into a series of massive gorges in Himalayan mountains. Until the 1880s it was unknown by which route it eventually reached the sea. It could have been any of the Yangtze, Mekong, Salween, Irrawaddy or Brahmaputra rivers all of which have headwaters this region.Kinthup, a Lepcha man from Sikkim employed as a pundit, had provided some evidence that the Tsangpo flowed into the Dihang (which is a tributary of the Brahmaputra) but he was not widely believed. By 1911 the connection was widely accepted. Another mystery remained: the river dropped from 9,000 feet (2,700 m) to 1,000 feet (300 m) in a distance of perhaps 100 miles (160 km) which is extremely steep for a river of this size. It seemed there must be a massive waterfall and, indeed, Kinthup had reported one 150 feet (46 m) high.

In 1911–12 as part of the Abor Expedition, the Survey of India conducted widespread surveying of the tributaries of the Brahmaputra. Morshead was in a team surveying the Dibang River while Frederick Bailey was surveying the Dihang. Oakes and Field of the Dihang team were first to measure the height of the 25,445-foot (7,756 m) Namcha Barwa and, from Dibang, Morshead confirmed the height – the separate measurements were able to provide a very accurate location.

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