(CNN) -- At least 200 structures have been destroyed and 1,100 damaged after a dam on an eastern Iowa lake failed, unleashing a torrent of floodwaters, a spokesman for the governor said Sunday.
The Lake Delhi dam, about 45 miles north of Cedar Rapids, failed Saturday as a result of "massive rain -- a very unusually high amount this season," according to Jim Flansburg, communications director for Gov. Chet Culver.
It was unclear how many of the structures impacted by the ensuing floodwaters were residential homes, Flansburg said.
Culver planned to tour the affected areas Sunday afternoon, helping set sandbags out to stave off the rising Maquoketa River.
Culver told CNN Saturday that nearly 10 inches of rain had recently fallen in a 12-hour period in the area and was "too much water for the dam to hold."
Video: Dam breaks in Iowa, town evacuated
The roads on either side of the dam -- which were part of the cement dam's containment measures -- apparently gave out as a result of the rainfall, Flansburg said.
Video on Saturday showed massive amounts of water violently gushing from the pool behind the dam into the Maquoketa below. Nearby homes and buildings were under water up to their eaves.
No injuries were reported.
