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Iowa · County tornado history

Marshall County, Iowa tornadoes

NOAA’s Storm Prediction Center has recorded 39 tornadoes in Marshall County, Iowa from 1950 through 2024, about one every 1.9 years. That ranks it 34 of 99 counties in Iowa with a recorded tornado. The most recent was an EF1 on August 10, 2020.

By Twisters.us · Updated · How we count

Tornadoes since 1950
39
Since 2000
19
Strongest
F4, May 24, 1989
Most recent
EF1, August 10, 2020
Peak month
June (12)
Per 1,000 sq mi
69
FEMA tornado risk
Relatively Moderate

F0/EF0 1 2 3 4 5 · Lines run from where each tornado touched down to where it lifted; dots are short paths. Neighboring counties are outlined.

When tornadoes hit Marshall County

June has brought the most, 12 of 39. About 59% touched down between 3 pm and 9 pm (Central Standard Time, as the Storm Prediction Center records it).

By decade

More tornadoes in recent decades mostly reflects better detection and reporting (Doppler radar, storm spotters, damage surveys), especially for weak EF0 tornadoes, not necessarily more storms. The 2020s bar covers only 2020 to 2024.

How strong they were

Rating Estimated 3-second gust Tornadoes
F0 / EF0 Light damage: 65 to 85 mph (EF scale) 12
F1 / EF1 Moderate: 86 to 110 mph 16
F2 / EF2 Considerable: 111 to 135 mph 4
F3 / EF3 Severe: 136 to 165 mph 4
F4 / EF4 Devastating: 166 to 200 mph 1
F5 / EF5 Incredible: over 200 mph 0
EF-U Unknown: no damage to rate (mostly since 2016) 2

Tornadoes before February 2007 were rated on the original Fujita (F) scale; since then the National Weather Service uses the Enhanced Fujita (EF) scale. Wind speeds above are EF-scale estimates from damage, not measurements. See what the EF scale means.

The strongest tornadoes in Marshall County

Date Rating Path length Path width Deaths Injuries
May 24, 1989 F4 66 mi 150 yd
September 16, 1978 F3 31.8 mi 200 yd 6 45
April 23, 1961 F3 87.7 mi 800 yd 1 12
July 19, 2018 EF3 8.4 mi 1,200 yd 22
June 1, 1951 F3 1.5 mi 880 yd 7
April 10, 1981 F2 5.6 mi 500 yd 9
May 28, 1962 F2 0.1 mi 200 yd 5
June 6, 1969 F2 0.1 mi 200 yd
June 11, 1969 F2 1 mi 100 yd
June 11, 1966 F1 0.1 mi 50 yd

Deaths and injuries are for each tornado’s whole path, which can cross other counties.

The deadliest

The deadliest tornado to touch Marshall County was an F3 on September 16, 1978. It killed 6 people and injured 45 along its 31.8-mile path.

Most recent tornadoes

Date Rating Path length Path width Deaths Injuries
August 10, 2020 EF1 2.9 mi 100 yd
August 10, 2020 EF-U 0.4 mi 50 yd
August 10, 2020 EF-U 1 mi 50 yd
March 28, 2020 EF0 1.3 mi 75 yd
July 19, 2018 EF3 8.4 mi 1,200 yd 22
July 19, 2018 EF0 0.8 mi 40 yd
November 11, 2015 EF0 1.9 mi 100 yd
June 30, 2014 EF1 11 mi 190 yd

The official database ends with 2024. For storms since then, see the Storm Prediction Center’s reports and your local National Weather Service office.

FEMA’s tornado risk rating

FEMA’s National Risk Index rates the tornado risk in Marshall County as relatively moderate, with a score of 83 out of 100 compared with every other U.S. county. It estimates about 0.60 tornadoes a year here and an expected annual loss of about $4,486,623 to buildings, people and farming. The index mixes how often tornadoes strike with what is exposed and how well a community can recover, so a busy rural county can rate lower than a less active city.

Neighboring counties

Staying safe

When a tornado warning is issued, act at once. Go to a basement, storm shelter or safe room. With none, use a small windowless room on the lowest floor, as far from outside walls as you can, and cover your head and neck. Mobile homes and cars are not safe places to ride out a tornado: leave early for a sturdy building or shelter. Read the full tornado safety guide and the National Weather Service advice linked below.

Sources

Sources last checked 1 November 2026.

Frequently asked questions

How many tornadoes has Marshall County had?

39 from 1950 through 2024 in NOAA’s Storm Prediction Center database, 19 of them since 2000.

When was the last tornado in Marshall County?

The most recent in the official record was an EF1 on August 10, 2020. Later storms are not yet in the final database.

What was the strongest tornado in Marshall County?

An F4 on May 24, 1989, with a 66-mile path.

When is tornado season in Marshall County?

June has had the most tornadoes here. Across the U.S. the peak runs from spring into early summer, and the South also sees tornadoes in late fall and winter.