In 2008, the area around Lake Delton, Wisconsin (just south of Wisconsin Dells) received a foot (300mm) of rain around June 9, causing the lake level to come up significantly and rapidly, leading to a breach. This breach was not a dam break but where the lake broke out through the roadway embankment for County Highway A to generate a new flow path to the Wisconsin River. It actually drained the lake by 40 feet but caused terrible damage, actually taking out homes and creating a 400 ft wide channel just left filled with mud by the end. The 2 videos below show some of the destruction once the breach occurred.
In this second clip, the house being taken out just looks like a toy getting tossed by the water. The sheer amount of water and head difference driving it is so massive, the video probably does not do it justice.
The lake was reopened in the summer of 2009 but flood studies continue related to this event on the Wisconsin River. The interstate closer to the channel not far downstream was actually overtopped and had to be shutdown due to the flooding.
