Grundy County, Iowa severe weather history spans 350 recorded events between 1952 and 2025. The dominant hazard is thunderstorm wind, accounting for 34.3% of all recorded events. It ranks #1,489 nationally and #67 in Iowa.
350
Recorded events
1
Direct deaths
3
Direct injuries
$12.8M
Property damage
The record
What the Grundy County, Iowa severe weather history record shows
Across the archive, Grundy County, Iowa severe weather history averages 4.8 recorded events a year. The busiest stretch on record is the 2000s, with 107 events logged in that decade alone. Roughly 42 events fall before 1990 and 308 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The deadliest hazard in the Grundy County, Iowa record is tornado, responsible for 1 direct deaths. The costliest is tornado, with $7.0M 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 Grundy County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Thunderstorm Wind | 120 | 0 | $2.1M | 80 | 1960–2025 |
| Hail | 91 | 0 | $589K | 3 | 1960–2025 |
| Heavy Rain | 50 | 0 | $0 | 0 | 2009–2025 |
| Tornado | 41 | 1 | $7.0M | F4 | 1952–2025 |
| Flash Flood | 20 | 0 | $2.0M | 0 | 1999–2024 |
| Flood | 14 | 0 | $955K | 0 | 1998–2020 |
| Funnel Cloud | 13 | 0 | $0 | 0 | 2007–2022 |
| Lightning | 1 | 0 | $100K | 0 | 2004–2004 |
Decade by decade
Grundy County, Iowa severe weather history by decade
Reporting practice changed over time — early decades are undercounted, not calmer.
Tornado tracks
Paths crossing this county
44 mapped tornado paths intersect this county: 39 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 |
|---|---|---|---|---|---|
| 2008-05-25 | EF5 | 9 | 70 | 41.0 mi | Touched down here |
| 1989-05-24 | EF4 | 0 | 0 | 66.0 mi | Crossed in |
| 1989-05-30 | EF4 | 0 | 3 | 11.0 mi | Crossed in |
| 1960-04-16 | EF3 | 1 | 5 | 29.8 mi | Touched down here |
| 1990-06-28 | EF3 | 0 | 0 | 9.0 mi | Crossed in |
| 2001-05-10 | EF2 | 0 | 0 | 1.7 mi | Touched down here |
| 2001-05-10 | EF2 | 0 | 0 | 8.0 mi | Touched down here |
| 1999-07-02 | EF2 | 0 | 0 | 8.5 mi | Crossed in |
| 1991-03-22 | EF2 | 0 | 0 | 20.0 mi | Touched down here |
| 1971-05-31 | EF2 | 0 | 0 | 4.5 mi | Crossed in |
Significant events
Deadliest events on record in Grundy County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Jun 3, 1952 | Tornado | 1 | 2 | $200K | |
| Jul 10, 2000 | Flash Flood | COUNTYWIDE | 0 | 1 | $200K |
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Public reported water coming onto westbound lane of County Highway D17 from South Beaver Creek. Report came via social media. The Iowa DOT also reported flooding along Iowa Highway 175 with the highway being reduced to one lane near Reinbeck.
At 9:45 p.m on 8/31 in Grundy County, Iowa just south of County HWY D25 on J Ave our farm lost 3/4 of it's machine shed roof on the SE side. Part of the roof landed straight east short of 300 ft to 400 ft down driveway and the other part west in front of the shed but on the NE side. More steel was to the NE about 300 ft to 400 ft and just missed our house. The steel bent over the cable dish. There was insulation splattered all over the garage and house to the NE of where roof went off and both garage doors were damaged.
Tornado touched down in open fields. Dust debris blown across highway 14 as it crossed. The track was intermittent and the tornado was reported to be multiple vortex at times with two tornadoes on the ground at one point northeast of Grundy Center.
Context
Risk, population and federal disasters
Very Low
FEMA NRI risk rating
12,384
Population (ACS)
$199K
Median home value
15
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Aug 17, 2020 | Severe Storm | SEVERE STORMS | DR |
| Mar 23, 2020 | Biological | COVID-19 PANDEMIC | DR |
| Mar 13, 2020 | Biological | COVID-19 | EM |
| Aug 5, 2014 | Severe Storm | SEVERE STORMS, TORNADOES, STRAIGHT-LINE WINDS, AND FLOODING | DR |
| Jul 31, 2013 | Severe Storm | SEVERE STORMS, TORNADOES, AND FLOODING | DR |
| Jul 2, 2013 | Severe Storm | SEVERE STORMS, TORNADOES, AND FLOODING | DR |
Quick answers
Frequently asked
How many severe weather events have been recorded in Grundy County, Iowa?
350 events are on record between 1952 and 2025, causing 1 direct deaths and $12.8M in property damage.
What is the most common severe weather hazard in Grundy County?
Thunderstorm Wind, with 120 recorded events — 34.3% of everything in the archive for this county.
How many tornadoes have crossed Grundy County?
44 mapped tornado paths intersect the county boundary; 39 of them touched down inside it. This is derived from path geometry, not county-tagged reports.
How many federal disaster declarations cover Grundy County?
15 federal disaster declarations from FEMA include Grundy County, each tied to a specific incident period.
How risky is Grundy County compared with the rest of the country?
FEMA's National Risk Index rates Grundy County as very low risk, placing it in the 13 percentile of its state for expected annual loss.
Where does the Grundy 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
- Greene County 335
- Guthrie County 515
- Fremont County 361
- Hamilton County 438
- Franklin County 366
- Hancock County 318
Cite this page
“Grundy County, Iowa.” Severe Weather History. severeweatherhistory.com/county/iowa/grundy-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.