Union County, South Dakota severe weather history spans 491 recorded events between 1954 and 2025. The dominant hazard is hail, accounting for 32.2% of all recorded events. It ranks #907 nationally and #29 in South Dakota.
491
Recorded events
0
Direct deaths
4
Direct injuries
$68.8M
Property damage
The record
What the Union County, South Dakota severe weather history record shows
Across the archive, Union County, South Dakota severe weather history averages 6.9 recorded events a year. The busiest stretch on record is the 2010s, with 156 events logged in that decade alone. Roughly 47 events fall before 1990 and 444 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The costliest is flood, with $57.1M in reported property damage. In total, 7 distinct hazard types appear in this county archive, each listed with its own dated record below.
By hazard type
Every hazard type recorded in Union County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Hail | 158 | 0 | $5.3M | 3 | 1959–2025 |
| Thunderstorm Wind | 151 | 0 | $782K | 80 | 1973–2025 |
| Flood | 135 | 0 | $57.1M | 0 | 2006–2024 |
| Tornado | 24 | 0 | $3.0M | F3 | 1954–2014 |
| Flash Flood | 19 | 0 | $0 | 0 | 1999–2025 |
| Lightning | 2 | 0 | $2.5M | 0 | 2004–2020 |
| Heavy Rain | 2 | 0 | $100K | 0 | 1996–2002 |
Decade by decade
Union County, South Dakota severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
24 mapped tornado paths intersect this county: 21 touched down inside it and 3 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 1965-06-07 | EF3 | 0 | 0 | 0.1 mi | Touched down here |
| 1987-07-07 | EF2 | 0 | 0 | 8.0 mi | Touched down here |
| 1978-07-05 | EF2 | 0 | 0 | 20.8 mi | Touched down here |
| 2013-10-04 | EF1 | 0 | 0 | 5.9 mi | Crossed in |
| 2013-10-04 | EF1 | 0 | 0 | 6.5 mi | Touched down here |
| 1990-06-16 | EF1 | 0 | 0 | 9.0 mi | Crossed in |
| 1985-08-12 | EF1 | 0 | 0 | 20.0 mi | Crossed in |
| 1954-05-27 | EF1 | 0 | 0 | 0.1 mi | Touched down here |
| 2014-05-11 | EF0 | 0 | 0 | 2.4 mi | Touched down here |
| 2005-06-04 | EF0 | 0 | 0 | 0.1 mi | Touched down here |
Significant events
Deadliest events on record in Union County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Jul 5, 1994 | Thunderstorm Wind | Beresford | 0 | 2 | $50K |
| Apr 21, 2004 | Lightning | ELK PT | 0 | 1 | $2K |
| Jul 5, 1994 | Tornado | Big Springs | 0 | 1 | $50K |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Lightning struck a single-story apartment building and initiated a fire which burned through the entire attic of the building. Crews from North Sioux City and three nearby cities attacked the fire for around two hours. All twenty apartments were severely damaged, displacing all residents. Property damage costs are rough estimates.
Repeated heavy rains caused record flooding of the Big Sioux River. Farmland and other lowlands including numerous roads were flooded. Some roads were damaged, and some secondary roads were washed out. A few farm homes, other farm buildings, and some fences were damaged by floodwaters. The river crested at a record 12.92 feet above flood stage at Hawarden, Iowa on June 17th. Interstate 29 was temporarily closed along a 22 mile stretch to facilitate levee building to divert some Big Sioux River water to McCook Lake, but the Interstate was re-opened when the river crested at a lower level than was feared. A levee breach across the river from Akron, Iowa, briefly aggravated lowland flooding before it was repaired.
A tornado crossed the Missouri River from Dakota County in Nebraska and entered Union County. The tornado severely damaged the roof of a house, and collapsed a chimney, carport and porch roof, and the walls of a garage in the same house. The tornado also caused tree damage, including trunks snapped, overturned an irrigation system, and damaged the roof, siding, and/or gutters of at least four other houses.
Context
Risk, population and federal disasters
Very Low
FEMA NRI risk rating
17,081
Population (ACS)
$301K
Median home value
19
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Aug 15, 2024 | Flood | SEVERE STORMS, STRAIGHT-LINE WINDS, AND FLOODING | DR |
| Apr 5, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Nov 18, 2019 | Severe Storm | SEVERE STORMS, TORNADOES, AND FLOODING | DR |
| Sep 23, 2019 | Flood | SEVERE STORMS AND FLOODING | DR |
| Jun 7, 2019 | Flood | SEVERE WINTER STORM, SNOWSTORM, AND FLOODING | DR |
Within the county
Most affected places
- Richland 234
- Elk Pt 205
- Alcester 179
- Jefferson 149
- Big Spgs 138
Quick answers
Frequently asked
How many severe weather events have been recorded in Union County, South Dakota?
491 events are on record between 1954 and 2025, causing 0 direct deaths and $68.8M in property damage.
What is the most common severe weather hazard in Union County?
Hail, with 158 recorded events — 32.2% of everything in the archive for this county.
How many tornadoes have crossed Union County?
24 mapped tornado paths intersect the county boundary; 21 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Union County?
19 federal disaster declarations from FEMA include Union County, each tied to a specific incident period.
How risky is Union County compared with the rest of the country?
FEMA's National Risk Index rates Union County as very low risk, placing it in the 37 percentile of its state for expected annual loss.
Where does the Union County, South Dakota severe weather history data come from?
Every figure is drawn from United States federal public-domain records: NOAA/NCEI Storm Events for the event archive, NOAA SPC SVRGIS for mapped tornado paths, FEMA for disaster declarations and risk ratings, and the U.S. Census for population context. Dates are shown in UTC and recent entries may still be revised by NOAA.
Nearby
Neighbouring counties
- Turner County 423
- Walworth County 410
- Tripp County 595
- Todd County 567
- Sully County 278
- Yankton County 531
Cite this page
“Union County, South Dakota.” Severe Weather History. severeweatherhistory.com/county/south-dakota/union-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.