FloodZoneMap.org

Flood — Union, SD

Jun 21, 2018

Primed by 1 to 3 inches of rainfall on June 17-18, starting June 20, the area was impacted adversely by several very slow moving mid-level waves which drifted across the northern and central Plains during the following week. High precipitable water and persistent lift forcing resulted in a widespread 4 to 9 inches of rainfall, inundating crop and pasture land as well as several roads.

Source: NOAA National Weather Service Storm Events Database (event 766635). Narrative written by NWS staff at the time of the event.

Flood Risk Context for Union, SD

This event is one of many recorded floods in Union County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.

View Union County flood data →

More Flood Stories

Flood$54.5M damage

Union, SD · Jun 21, 2024

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.

Read the full account →
Flood$1.2M damage

Union, SD · Mar 13, 2019

Rainfall of one to three inches on frozen ground and into a snow pack with between 2 and 5 inches of liquid water equivalent resulted in considerable overland flooding.||One of the hardest hit areas was around Yankton, where a No Travel Advisory was issued for the city on March…

Read the full account →
Flood$25K damage

Union, SD · Sep 14, 2019

Continued high dam releases, along with another period of very heavy rainfall in the middle of the month, pushed a small section of the lower Missouri River into flood late month.

Read the full account →
Flood$25K damage

Union, SD · Sep 12, 2019

Spurred by a period of excessive precipitation from September 10-12 that resulted in 5 to 10 inches of rainfall in the middle to upper reaches of the Big Sioux River Basin and 2 to 5 inches from Sioux Falls downstream, extreme rises occurred mid-month, with many basin locations…

Read the full account →