40
Recorded events
0
Direct deaths
10
Direct injuries
$5.4M
Property damage
Tornado in Cass County, Iowa: 40 recorded events between 1956 and 2024. The strongest on record measured F3. That places the county #620 nationally and #32 statewide for this hazard.
Decade by decade
Tornado in Cass County, Iowa: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for tornado in Cass County is the 2020s, when 9 of the county's 40 recorded events were logged. Comparing decades is useful for spotting active periods, but the earliest years are thin because systematic reporting for this hazard began later.
Within the Cass County archive, tornado makes up 7.3% of all recorded severe weather across 8 hazard types. Nationally the county sits at #620 for this hazard and #32 within Iowa, putting it in the 78.6 percentile of all U.S. counties.
Seasonality
Events by month
Jun is the peak month for tornado in Cass County with 13 recorded events, while Jan is the quietest. Seasonality here is a property of the archive as much as the climate: reports cluster where population and spotter networks are densest.
Tornado tracks
Paths crossing this county
| Date | Scale | Path length | Max width | Origin |
|---|---|---|---|---|
| 1974-05-13 | EF3 | 10.9 mi | 20 yd | Crossed in |
| 1964-04-20 | EF3 | 6.1 mi | 350 yd | Touched down here |
| 2021-12-15 | EF2 | 27.1 mi | 100 yd | Touched down here |
| 2007-05-06 | EF2 | 7.4 mi | 830 yd | Touched down here |
| 1984-06-07 | EF2 | 23.0 mi | 150 yd | Touched down here |
| 1976-06-13 | EF2 | 20.0 mi | 100 yd | Touched down here |
| 1970-05-12 | EF2 | 5.9 mi | 400 yd | Crossed in |
| 1965-05-25 | EF2 | 0.1 mi | 200 yd | Touched down here |
| 1964-08-27 | EF2 | 1.0 mi | 50 yd | Touched down here |
| 1963-04-18 | EF2 | 0.1 mi | 200 yd | Touched down here |
Significant events
Deadliest on record
| Date | Location | Scale | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Jun 7, 1984 | F2 | 0 | 8 | $2.5M | |
| Jun 23, 1985 | F1 | 0 | 1 | $250K | |
| Apr 21, 1964 | F3 | 0 | 1 | $25K |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jun 29, 2024 | WIOTA | EFU | $0 |
| Jun 29, 2024 | WIOTA | EFU | $0 |
| Jun 29, 2024 | LEWIS | EF0 | $1K |
| Jun 29, 2024 | MARNE | EFU | $0 |
| Apr 16, 2024 | ANITA MUNI ARPT | EF1 | $25K |
| Jul 12, 2023 | MARNE | EF0 | $5K |
| Jul 12, 2023 | MARNE | EF0 | $0 |
| Dec 15, 2021 | LORAH | EF0 | $25K |
| Dec 15, 2021 | LEWIS | EF2 | $300K |
| Jul 16, 2019 | FLETCHER CHAPEL | EFU | $0 |
Other hazards here
More from Cass County
- Thunderstorm Wind 203
- Hail 174
- Heavy Rain 82
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Tornado touched down on the southern Cass County line and moved northeast. The last 2 miles of the track showed an intermittent nature. Average path width was 100 to 200 yards wide with a maximum width of about one half mile. Estimated wind speed was 120 to 130 MPH.
Tornado developed northwest of Lewis and moved rapidly to the northeast. Damage occurred to several houses and trees along the path with mostly EF0 and EF1 ratings. Three high voltage steel towers were toppled providing the EF2 rating for this tornado. The tornado crossed Interstate 80 near milepost 59 blowing several semi onto their sides. The path was also observed in high resolution satellite imagery. This tornado then crossed into Audubon county.
Damage from this tornado was relayed by the Cass County Emergency Manager and the path was also found in high resolution satellite imagery. Some minor damage to trees and outbuildings occurred at one farmstead east of Marne with the remainder of the path through open cropland.
Quick answers
Frequently asked
How many tornado events are on record in Cass County, Iowa?
40 tornado events are recorded in Cass County between 1956 and 2024, causing 0 direct deaths.
What is the strongest tornado recorded in Cass County?
The strongest tornado on record in Cass County measured F3.
Where does the tornado data for Cass County come from?
All events come from the NOAA/NCEI Storm Events Database, the federal public-domain archive of severe weather reports. Dates are UTC, damage is as reported and not inflation-adjusted, and the most recent entries may still be revised.
Cite this page
“Tornado in Cass County, Iowa.” Severe Weather History. severeweatherhistory.com/county/iowa/cass-county/tornado/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.