Live
Active alerts for this county
Cass County, Iowa severe weather history spans 550 recorded events between 1956 and 2025. The dominant hazard is thunderstorm wind, accounting for 36.9% of all recorded events. It ranks #727 nationally and #25 in Iowa.
550
Recorded events
0
Direct deaths
11
Direct injuries
$17.1M
Property damage
The record
What the Cass County, Iowa severe weather history record shows
Across the archive, Cass County, Iowa severe weather history averages 8.0 recorded events a year. The busiest stretch on record is the 2000s, with 206 events logged in that decade alone. Roughly 65 events fall before 1990 and 485 from 1990 onward — a gap that reflects the expansion of NOAA reporting practice as much as the weather itself.
The costliest is tornado, with $5.4M 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 Cass County
| Hazard | Events | Deaths | Damage | Max | Span |
|---|---|---|---|---|---|
| Thunderstorm Wind | 203 | 0 | $4.4M | 94 | 1968–2025 |
| Hail | 174 | 0 | $1.5M | 3 | 1971–2025 |
| Heavy Rain | 82 | 0 | $0 | 0 | 2008–2024 |
| Tornado | 40 | 0 | $5.4M | F3 | 1956–2024 |
| Flash Flood | 34 | 0 | $4.3M | 0 | 1996–2019 |
| Flood | 10 | 0 | $1.4M | 0 | 1996–2019 |
| Funnel Cloud | 5 | 0 | $0 | 0 | 2011–2025 |
| Lightning | 2 | 0 | $60K | 0 | 2018–2018 |
Decade by decade
Cass 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 |
|---|---|---|---|---|---|
| 1974-05-13 | EF3 | 0 | 0 | 10.9 mi | Crossed in |
| 1964-04-20 | EF3 | 0 | 1 | 6.1 mi | Touched down here |
| 2021-12-15 | EF2 | 0 | 0 | 27.1 mi | Touched down here |
| 2007-05-06 | EF2 | 0 | 0 | 7.4 mi | Touched down here |
| 1984-06-07 | EF2 | 0 | 8 | 23.0 mi | Touched down here |
| 1976-06-13 | EF2 | 0 | 0 | 20.0 mi | Touched down here |
| 1970-05-12 | EF2 | 0 | 0 | 5.9 mi | Crossed in |
| 1965-05-25 | EF2 | 0 | 0 | 0.1 mi | Touched down here |
| 1964-08-27 | EF2 | 0 | 0 | 1.0 mi | Touched down here |
| 1963-04-18 | EF2 | 0 | 0 | 0.1 mi | Touched down here |
Significant events
Deadliest events on record in Cass County
| Date | Type | Location | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Jun 7, 1984 | Tornado | 0 | 8 | $2.5M | |
| May 22, 1998 | Thunderstorm Wind | ATLANTIC | 0 | 1 | $50K |
| Jun 23, 1985 | Tornado | 0 | 1 | $250K | |
| Apr 21, 1964 | Tornado | 0 | 1 | $25K |
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.
Large hail and severe winds combined to produce damage to crop and houses. A semi was blown over on Interstate 80 near mile marker 71 by the strong winds. The wind driven hail stripped crops across the far northeast corner of the county.
Context
Risk, population and federal disasters
Relatively Low
FEMA NRI risk rating
13,096
Population (ACS)
$150K
Median home value
19
Federal declarations
| Declared | Incident | Title | Type |
|---|---|---|---|
| Feb 23, 2022 | Severe Storm | SEVERE STORMS, 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 |
| Mar 2, 2010 | Severe Storm | SEVERE WINTER STORM | DR |
| Feb 25, 2010 | Severe Storm | SEVERE WINTER STORMS AND SNOWSTORM | DR |
Within the county
Most affected places
- Atlantic 162
Quick answers
Frequently asked
How many severe weather events have been recorded in Cass County, Iowa?
550 events are on record between 1956 and 2025, causing 0 direct deaths and $17.1M in property damage.
What is the most common severe weather hazard in Cass County?
Thunderstorm Wind, with 203 recorded events — 36.9% of everything in the archive for this county.
How many tornadoes have crossed Cass 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 Cass County?
19 federal disaster declarations from FEMA include Cass County, each tied to a specific incident period.
How risky is Cass County compared with the rest of the country?
FEMA's National Risk Index rates Cass County as relatively low risk, placing it in the 60 percentile of its state for expected annual loss.
Where does the Cass 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
- Carroll County 461
- Cedar County 498
- Calhoun County 370
- Cerro Gordo County 605
- Butler County 509
- Cherokee County 381
Cite this page
“Cass County, Iowa.” Severe Weather History. severeweatherhistory.com/county/iowa/cass-county/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.