a

As new areas were flooding Tuesday, some cities and towns were cleaning up after the waters receded while others downstream were piling sandbags and taking other measures to protect against the oncoming swelled currents. Some normal, unassuming tributaries ballooned into rushing rivers, damaging homes, buildings and bridges.

"Normally, this river is barely a trickle," 71-year-old Hank Howley said as she watched the Big Sioux's waters gush over a broken and partially sunken rail bridge in North Sioux City, South Dakota, on Monday. "Really, you could just walk across it most days."

South Dakota state geologist Tim Cowman said that the five major rivers in the state's southeastern corner have crested and are dropping, albeit slowly. The last of those rivers to crest, the James, did so early Tuesday.