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Union County, Iowa severe weather history spans 406 recorded events between 1956 and 2025. The dominant hazard is thunderstorm wind, accounting for 34.0% of all recorded events. It ranks #1,230 nationally and #52 in Iowa.
406
Recorded events
0
Direct deaths
9
Direct injuries
$44.8M
Property damage
The record
What the Union County, Iowa severe weather history record shows
Across the archive, Union County, Iowa severe weather history averages 5.9 recorded events a year. The busiest stretch on record is the 2010s, with 151 events logged in that decade alone. Roughly 43 events fall before 1990 and 363 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The costliest is tornado, with $39.7M in reported property damage. In total, 8 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 |
|---|---|---|---|---|---|
| Thunderstorm Wind | 138 | 0 | $1.7M | 89 | 1957–2025 |
| Hail | 120 | 0 | $1.2M | 3 | 1956–2025 |
| Heavy Rain | 59 | 0 | $5K | 0 | 2008–2025 |
| Tornado | 42 | 0 | $39.7M | F4 | 1962–2025 |
| Flash Flood | 26 | 0 | $1.6M | 0 | 2000–2019 |
| Funnel Cloud | 13 | 0 | $0 | 0 | 1996–2024 |
| Flood | 5 | 0 | $450K | 0 | 1996–2015 |
| Lightning | 3 | 0 | $95K | 0 | 2001–2011 |
Decade by decade
Union County, Iowa severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
40 mapped tornado paths intersect this county: 33 touched down inside it and 7 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 1999-04-08 | EF4 | 0 | 1 | 56.0 mi | Touched down here |
| 1995-05-27 | EF4 | 0 | 2 | 57.0 mi | Touched down here |
| 2001-04-11 | EF3 | 0 | 0 | 76.5 mi | Crossed in |
| 1979-03-29 | EF3 | 0 | 4 | 57.0 mi | Crossed in |
| 2024-04-26 | EF2 | 0 | 0 | 6.7 mi | Touched down here |
| 2024-04-26 | EF2 | 0 | 0 | 13.9 mi | Touched down here |
| 2024-04-26 | EF2 | 0 | 0 | 9.7 mi | Crossed in |
| 2012-04-14 | EF2 | 0 | 2 | 16.6 mi | Crossed in |
| 1972-06-13 | EF2 | 0 | 0 | 2.0 mi | Touched down here |
| 1964-04-12 | EF2 | 0 | 0 | 9.4 mi | Touched down here |
Significant events
Deadliest events on record in Union County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Apr 14, 2012 | Tornado | CROMWELL | 0 | 2 | $5.0M |
| May 28, 1995 | Tornado | Creston to | 0 | 2 | $3.0M |
| Mar 30, 1979 | Tornado | 0 | 2 | $2.5M | |
| Jun 12, 2004 | Thunderstorm Wind | AFTON | 0 | 1 | $2K |
| Apr 8, 1999 | Tornado | CRESTON | 0 | 1 | $2.0M |
| May 22, 1998 | Thunderstorm Wind | CRESTON | 0 | 1 | $10K |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
This tornado continued in from Adams county. NWS storm survey confirmed a strong EF2 tornado. It entered Union county just southwest of Cromwell and tracked east-northeast through the far northwest portion of Creston. The Greater Regional Medical Center and Southwest Community College sustained EF2 damage with the worst occurring to the Green Hills Education Center. The tornado continued tracking northeast and damaged a few farmsteads northeast of Creston.
A two-story brick building with wooden roof and shingles was damaged. Roof and shingles were blown off. A 4 foot diameter tree was uprooted in the city park and 3 air handling units were blown off of the East Union High School in Afton. Tin was blown off the feed mill.
This tornado formed between the BNSF railroad and Highway 34 west of Afton and took a track very similar to a tornado which occurred earlier in the hour. It produced EF2 damage to several house on either side of Highway 34 as it travelled to the northeast. The tornado crossed Three Mile Lake just upstream of the dam and impacted a structure in the Wildlife Management Building area just a few hundred yards from the one impacted in the earlier tornado. This tornado then moved northeast through rural Union County impacting another farmstead producing EF2 damage. The tornado dissipated in the north central portion of Union County near the intersection of Pheasant Avenue and 130th Street.
Context
Risk, population and federal disasters
Relatively Low
FEMA NRI risk rating
11,993
Population (ACS)
$122K
Median home value
21
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| May 14, 2024 | Tornado | SEVERE STORMS AND TORNADOES | DR |
| Mar 23, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Mar 23, 2019 | Flood | SEVERE STORMS AND FLOODING | DR |
| Jul 29, 2010 | Severe Storm | SEVERE STORMS, FLOODING, AND TORNADOES | DR |
| Mar 2, 2010 | Severe Storm | SEVERE WINTER STORM | DR |
Within the county
Most affected places
- Creston 156
Quick answers
Frequently asked
How many severe weather events have been recorded in Union County, Iowa?
406 events are on record between 1956 and 2025, causing 0 direct deaths and $44.8M in property damage.
What is the most common severe weather hazard in Union County?
Thunderstorm Wind, with 138 recorded events — 34.0% of everything in the archive for this county.
How many tornadoes have crossed Union County?
40 mapped tornado paths intersect the county boundary; 33 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Union County?
21 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 relatively low risk, placing it in the 50 percentile of its state for expected annual loss.
Where does the Union County, Iowa 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
- Taylor County 442
- Van Buren County 327
- Tama County 431
- Wapello County 594
- Story County 1,100
- Warren County 883
Cite this page
“Union County, Iowa.” Severe Weather History. severeweatherhistory.com/county/iowa/union-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.