Behind the China-Nepal mudslide: What caused its devastating force?

The China-Nepal border mudslide has caused heavy casualties and left many people missing on both sides.

What triggered the disaster, and what made its destructive force so immense? "This event was initially caused by a very large ice rock avalanche." Fan Xuanmei, a geohazard expert from Chengdu University of Technology, explains the factors behind the disaster and the extraordinary energy released by the mudslide.