Döda fallet

Döda fallet is a former whitewater rapid in of the river Indalsälven in Ragunda Municipality in the eastern part of the province of Jämtland in Sweden. Glacial debris had blocked the course of the Indalsälven at Döda fallet for thousands of years, creating a reservoir of glacial meltwater 25 km long known as Ragundasjön, which overflowed over a natural spillway that bypassed this dam of debris, in a long high steep rapid known as Gedungsen or Storforsen. It was one of the most impressive rapids in Sweden with a total fall height of about 35 meters and a large water discharge.

The lake disappeared and the falls went dry in the 1796 Ragunda lake burst disaster after a flood rerouted the river through a small canal constructed to bypass the falls, carving a new channel and emptying the lake in four hours.

Source: Wikipedia