Lyon County, Iowa severe weather history spans 436 recorded events between 1951 and 2025. The dominant hazard is hail, accounting for 39.7% of all recorded events. It ranks #1,115 nationally and #46 in Iowa.
436
Recorded events
1
Direct deaths
2
Direct injuries
$32.5M
Property damage
The record
What the Lyon County, Iowa severe weather history record shows
Across the archive, Lyon County, Iowa severe weather history averages 5.9 recorded events a year. The busiest stretch on record is the 2000s, with 145 events logged in that decade alone. Roughly 38 events fall before 1990 and 398 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The deadliest hazard in the Lyon County, Iowa record is tornado, responsible for 1 direct deaths. The costliest is flood, with $17.2M 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 Lyon County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Hail | 173 | 0 | $500K | 4 | 1966–2025 |
| Thunderstorm Wind | 119 | 0 | $462K | 78 | 1956–2025 |
| Flood | 85 | 0 | $17.2M | 0 | 2006–2024 |
| Tornado | 43 | 1 | $10.2M | F2 | 1951–2025 |
| Flash Flood | 12 | 0 | $4.1M | 0 | 2001–2024 |
| Funnel Cloud | 2 | 0 | $0 | 0 | 2014–2019 |
| Lightning | 1 | 0 | $100K | 0 | 2011–2011 |
| Heavy Rain | 1 | 0 | $0 | 0 | 2012–2012 |
Decade by decade
Lyon County, Iowa severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
49 mapped tornado paths intersect this county: 44 touched down inside it and 5 crossed in from a neighbouring county. This comes from path geometry, not county-tagged reports.
| Date | Scale | Deaths | Injuries | Path length | Origin |
|---|---|---|---|---|---|
| 2010-06-25 | EF4 | 0 | 13 | 13.7 mi | Touched down here |
| 1971-05-31 | EF3 | 0 | 0 | 46.5 mi | Crossed in |
| 1986-04-26 | EF2 | 1 | 4 | 18.5 mi | Touched down here |
| 2008-05-01 | EF2 | 0 | 0 | 13.0 mi | Crossed in |
| 1993-06-07 | EF2 | 0 | 5 | 10.0 mi | Touched down here |
| 1993-05-07 | EF2 | 0 | 0 | 11.5 mi | Touched down here |
| 1986-04-26 | EF2 | 0 | 0 | 9.5 mi | Touched down here |
| 1978-07-06 | EF2 | 0 | 0 | 14.2 mi | Touched down here |
| 1954-06-19 | EF2 | 0 | 0 | 2.3 mi | Touched down here |
| 2025-07-28 | EF1 | 0 | 0 | 2.1 mi | Touched down here |
Significant events
Deadliest events on record in Lyon County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Apr 27, 1986 | Tornado | 1 | 2 | $2.5M |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Very heavy rain caused flash flooding, forcing streams including the Kanaranzi River, Rio Grand, and Moon Creek to overflow and flood homes, garages, and storage sheds in George. Flooding of roads and other lowlands was widespread. A road washed out and at least four bridges were damaged in George.
Repeated heavy rains caused record flooding of the Rock River. Numerous homes, businesses, roads, farmland, and other low areas were flooded, forcing many people to evacuate their homes and rely on Red Cross and other volunteer assistance for several days. The flooding was especially severe in Rock Rapids, where the river crested at a record 13.98 feet above flood stage on June 17th.
A tornado destroyed two hog confinement buildings, killing about 12 hogs, numerous outbuildings, a metal farm building, tore the roof off a house and damaged at least 6 other houses, and caused damage to other farm buildings, power lines, vehicles, and trees, before moving out of Lyon County and into Osceola County.
Context
Risk, population and federal disasters
Very Low
FEMA NRI risk rating
12,162
Population (ACS)
$230K
Median home value
16
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Jun 24, 2024 | Severe Storm | SEVERE STORMS, FLOODING, STRAIGHT-LINE WINDS, 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 |
| Aug 20, 2018 | Severe Storm | SEVERE STORMS, TORNADOES, STRAIGHT-LINE WINDS, AND FLOODING | DR |
| Jul 24, 2014 | Flood | SEVERE STORMS, TORNADOES, STRAIGHT-LINE WINDS, AND FLOODING | DR |
Within the county
Most affected places
- Granite 121
Quick answers
Frequently asked
How many severe weather events have been recorded in Lyon County, Iowa?
436 events are on record between 1951 and 2025, causing 1 direct deaths and $32.5M in property damage.
What is the most common severe weather hazard in Lyon County?
Hail, with 173 recorded events — 39.7% of everything in the archive for this county.
How many tornadoes have crossed Lyon County?
49 mapped tornado paths intersect the county boundary; 44 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Lyon County?
16 federal disaster declarations from FEMA include Lyon County, each tied to a specific incident period.
How risky is Lyon County compared with the rest of the country?
FEMA's National Risk Index rates Lyon County as very low risk, placing it in the 19 percentile of its state for expected annual loss.
Where does the Lyon 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
- Lucas County 296
- Madison County 402
- Louisa County 247
- Mahaska County 428
- Linn County 1,170
- Marion County 710
Cite this page
“Lyon County, Iowa.” Severe Weather History. severeweatherhistory.com/county/iowa/lyon-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.