During the night of July 29, 1983, the glacier thawing water in Peilong stream, a tributary in the upstream of Parlung Zangbo River, combined with ceaseless rains, resulted in a large-scaled glacier mud-rock flow in Peilong. Mingling with ice blocks, giant rocks and clays, it flew down and formed a giant piled fan. The quantity of the mud-rock flow was as much as 1 million cubic meters. A concrete bridge with a length of 32 meters and a height of 10 meters was destroyed. The Sichuan-Tibet highway longer than 320 meters was damaged. It was estimated that the economic loss was over half a million yuan. Afterwards, glacier mud-rock flows happened once and again; such as the mud-rock flow in September 21 in the same year; the one on June 16, 1984 and the one on July 27. The mud-rock flows were all of paroxysmal.

　　On June 18, 1985, because of storms, mud-rock flow happened again. At the beginning, the mud-rock flow mixed with ice blocks and water; later it mingled with sands and stones; it flew with a flowing rate of 1-2 meters per second; the mud flow killed 17 people, destroyed 5 houses and 79 trucks and caused an economic loss of more than 5 million Yuan. This mud-rock flow finally formed a mud-rock flow piled fan of 1-2 kilometers with a width of 400-500 meters in the Parlung Zangbo River. The piled rocks and soils were as thick as 30-40 meters. Parlung Zangbo River was dammed once again. The water level rose up and the highway was forced to be reconstructed by increasing the base for more than 100 meters after the highway along the river was all flooded.