At least 18 people are dead and as many as 200 are missing after a piece of a Himalayan glacier broke off Sunday (Feb. 7), triggering an avalanche and flash flood that smashed through a nearby hydroelectric dam. A second dam, located further downstream, was also damaged by the flood, according to the BBC.

Video recorded by bystanders shows the raging floodwaters surging through a rocky valley in Uttarakhand – an Indian state in the Himalayas bordering China and Nepal – before ripping through the dam with a battering ram of rocks, mud, ice and debris.