Zhugqu County was the worst hit location, where mud submerged houses and tore multi-story blocks of flats to pieces. The seat of Zhouqu County was densely populated, with 50,000 people (42,000 of them are permanent population) in an area of . After the heavy rain, there was a buildup of water behind a dam of debris blocking a small river to the north of the city of Zhugqu; when the dam broke, around of mud and rocks swept through the town, in a surge reported as up to five stories high, covering more than 300 low-rise homes and burying at least one village entirely. The mudslide left an area long by wide in average leveled by mud with average thickness of . According to Gyurme Dorje's
Tibet Handbook, the forest region of Zhugqu has, since the 1950s, "shrunk by 30% and the reserve of timber reduced by 25% due to overfelling. The sand in the river water has increased by 60%, and the water volume has reduced by 8%, resulting in increased flooding and drought." Furthermore, in this county there were between 47 and 53 hydroelectric construction projects in recent years, with 41 completed and 12 approaching deadline, according to government data. These together have caused 749,000 tons of water and soil erosion and over 3,000,000 cubic meters of bulldozed material. In 2006, a
Lanzhou University report concluded that these projects have made the whole area a volatile danger-zone.
The Christian Science Monitor reported that two science researchers had predicted the mudslides in 1997. The ''
People's Daily'' has argued that the mudslide was due to a "perfect storm" of natural events, including "soft" "weathered" rock, heavy rainfall, drought, and the
Sichuan earthquake two years before. Authorities dismissed claims that the mudslides were "man-made". == Relief ==