Flood in Union County, South Dakota

Rainfall amounts across Union County from June 20-22 ranged from around a third of an inch across southern areas to 1 to 2 inches across northern areas. Farther north and upstream, 6 to 10 inches of rain fell across portions of southeast South Dakota and northwest Iowa, with locally higher amounts in excess of 12 inches.

This rainfall resulted in record flooding along the Big Sioux River and extensive overland flooding along the adjoining flood plain. County-wide, 44 residences were destroyed and another 182 received minor to major flood damage. Estimated losses exceed 52 million dollars. At the peak of the flooding, there were an estimated 20 to 30 water rescues.

Residents along Northshore and Penrose Drives on the north side of McCook Lake were evacuated on the evening of June 23 as flood waters rose rapidly. Catastrophic damage ensued, with at least 26 homes declared a total loss and nearby infrastructure destroyed. Interstate 29 was inundated with water north of North Sioux City and closed June 23. The road reopened two days later on June 25. The railroad bridge crossing the Big Sioux River at North Sioux City also collapsed due to flooding.

Preliminary damage assessments estimate loss to public infrastructure across the county to be 2.16 million.

For additional information on river flooding, please see other flood entries for Union County.

A multi-day significant heavy rainfall event from June 20-22 resulted in widespread rain totals between 5 and 10 inches with pockets in excess of 15 inches across portions of southeast South Dakota, northwest Iowa, and southwest Minnesota. As rainfall reached area streams and rivers, major to record flooding was observed, devastating several towns and communities. Extensive overland flooding also resulted in significant impacts and damages. All river crest information is preliminary until made official by the gauge owner.

A Presidential Disaster Declaration was signed for Aurora, Bon Homme, Brule, Charles Mix, Clay, Davison, Douglas, Gregory, Hanson, Hutchinson, Lake, Lincoln, McCook, Miner, Minnehaha, Moody, Sanborn, Turner, Union, and Yankton Counties.