Thunderstorms during 1984 produced significant rainfall and subsequent runoff that caused substantial flooding in eastern Nebraska and southeastern South Dakota. The storms ocurred in rapid succession over the area, and the rain fell on ground that was near saturation from greater-than-normal precipitation during April and May. Flooding ocurred in the Loup River, Blue River, Platte River, Elkhorn River, and Weeping Water Creek basins in Nebraska and the James River, Vermillion River, and Big Sioux river basins in South Dakota. Record and near-record peak discharges occurred on many streams. The floodflows from tributary streams caused the highest stages and the most widespread flooding along the Missouri River from Sioux City, Iowa, to Rulo, Nebraska, since April 1952. (USGS)