 In the Wakhan Corridor of Afghanistan 28 of 30 glaciers examined retreated significantly between 1976 – 2003, with an average retreat of 11 m (36 ft) per year. One of these glaciers, the Zemestan Glacier, retreated 460 m (1,510 ft) during this period, not quite 10 % of its 5.2 km (3.2 mi) length. In examining 612 glaciers in China between 1950 and 1970, 53 % of the glaciers studied were retreating. After 1990, 95 % of these glaciers were measured to be retreating, indicating that retreat of these glaciers was becoming more widespread. Glaciers in the Mount Everest region of the Himalayas are all in a state of retreat. The Rongbuk Glacier, draining the north side of Mount Everest into Tibet, has been retreating 20 m (66 ft) per year. In the Khumbu region of Nepal along the front of the main Himalaya of 15 glaciers examined from 1976 – 2007 all retreated significantly and the average retreat was 28 m (92 ft) per year. The most famous of these, the Khumbu Glacier, retreated at a rate of 18 m (59 ft) per year from 1976 – 2007. In India, the Gangotri Glacier retreated 1,147 m (3,763 ft) between the years 1936 and 1996 with 850 m (2,790 ft) of that retreat occurring in the last 25 years of the 20th century. However, the glacier is still over 30 km (19 mi) long. In Sikkim, 26 glaciers examined between the years 1976 and 2005 were retreating at an average rate of 13.02 m (42.7 ft) per year. Overall, glaciers in the Greater Himalayan region that have been studied are retreating an average of between 18 and 20 m (59 and 66 ft) annually. The only region in the Greater Himalaya that has seen glacial advances is in the Karakoram Range and only in the highest elevation glaciers, but this has been attributed possibly increased precipitation as well as to the correlating glacial surges, where the glacier tongue advances due to pressure build up from snow and ice accumulation further up the glacier. Between the years 1997 and 2001, 68 km (42 mi) long Biafo Glacier thickened 10 to 25 m (33 to 82 ft) mid-glacier, however it did not advance.
