Heavy rain and snow swelled the rivers of Indiana, Illinois, and Kentucky, pushing many past flood stage during the first two weeks of January 2005. The flooding occurred after several days of rain and snow fell on the already saturated ground of the U.S. Midwest. Since the water could not be absorbed into the soaked ground, it ran off as flood water. The storms were followed by warm temperatures, which melted the snow and produced further flooding. By January 17, some of the flooding had started to recede, but large tracts of land along the Ohio and Wabash Rivers were still under water.
The Ohio River becomes a tributary of the Mississippi River directly south of Cairo, Illinois, a small city on the spit of land where the rivers converge. Brown, sediment-laden water flowing generally northeast to south from the Ohio River is distinct from the green and relatively sediment-poor water of the Mississippi River (flowing northwest to south). The color of the rivers in this image is reversed from the usual condition of a green Ohio and a brown Mississippi.