Nepal, Oct. 28 -- A drone filming mountain views on August 26 captured the onset of the Bhotekoshi disaster. Its pilot, intent on the shot, did not notice. Far off in the frame, a plume of ice and rock dust rose as about 132 million cubic metres of rock and glacier ice broke from the north face of Langtang Lirung. According to ICIMOD's preliminary reconstruction, the debris surge reached the Nepal-China border corridor in about seven minutes. Existing warning systems, built around rainfall and river levels, were not designed to detect it, and text alerts reached people only 38 minutes after the collapse. As of mid-October, at least 1,451 people in Nepal have been killed, and 5,745 remain missing.

That same day, the cabinet decided that d...