The dam keeper ordered the reservoir to be drained, but the flow rate continued to increase.

At 4:00pm, inhabitants of Desná were warned, and at 4:15pm, the dam burst with 250,000 cubic meters of water inside, which swept through the town.

[6] A court in 1932 acquitted those who had worked on the dam of all charges, and stated that the cause of the collapse was a geological instability that was too deep to detect during construction.

[6][1] A 1996 study by SG Geotechnika a.s. found that the absence of a sufficient geotechnical survey resulted in errors in the project, specifically not taking into account the great strength of the compressible layers below the dam body and their unacceptable permeability, and the excessively large hydraulic gradient of the water.

[6][7] The ruins of the dam are currently a Czech Republic cultural monument and a European Union Special Area of Conservation.