Tornadoes · United States · Iowa
1971 tornadoes in Iowa
33 tornadoes touched down in Iowa in 1971, 19 percent below the average of the record for the state. They killed 1 people and injured 27. 1 were rated F4 or EF4 and above.
The rating scale
Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 mph
Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.
F3158 to 206 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 mph
Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.
Unrated
The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.
Every tornado in Iowa in 1971
May 5 3 tornadoes
May 6 1 tornado
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 6 | 10:30 AM CDT | F1 | Mills | 1.0 | 100 | $50 to $500 |
May 18 7 tornadoes
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 18 | 3:00 PM CDT | F0 | Mahaska | 0.1 | 10 | $50,000 to $500,000 | ||
| May 18 | 3:15 PM CDT | F1 | Marion | 0.1 | 10 | $5,000 to $50,000 | ||
| May 18 | 4:08 PM CDT | F3 | Benton | 4.3 | 300 | $5,000 to $50,000 | ||
| May 18 | 4:12 PM CDT | F3 | Benton | 4.3 | 200 | $50,000 to $500,000 | ||
| May 18 | 5:00 PM CDT | F1 | Keokuk | 0.1 | 10 | $5,000 to $50,000 | ||
| May 18 | 6:23 PM CDT | F1 | Wapello | 0.1 | 10 | $5,000 to $50,000 | ||
| May 18 | 6:45 PM CDT | F1 | Iowa | 5.1 | 100 | $5,000 to $50,000 |
May 23 3 tornadoes
May 31 8 tornadoes
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 31 | 2:15 PM CDT | F3 | O'Brien to MN | 46.5 | 100 | $50,000 to $500,000 | ||
| May 31 | 2:20 PM CDT | F3 | Osceola | 8.6 | 250 | $50,000 to $500,000 | ||
| May 31 | 3:05 PM CDT | F3 | Dickinson | 8.0 | 200 | $50,000 to $500,000 | ||
| May 31 | 6:15 PM CDT | F2 | Hardin | 4.5 | 300 | $50,000 to $500,000 | ||
| May 31 | 7:20 PM CDT | F1 | Grundy | 2.3 | 200 | |||
| May 31 | 7:20 PM CDT | F1 | Grundy | 2.3 | 200 | |||
| May 31 | 7:30 PM CDT | F2 | Black Hawk | 1.0 | 200 | $5,000 to $50,000 | ||
| May 31 | 8:30 PM CDT | F3 | Tama | 9.4 | 600 | $50,000 to $500,000 |
June 6 4 tornadoes
June 24 1 tornado
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| June 24 | 7:00 PM CDT | F3 | Fayette | 0.1 | 200 | 1 | $50,000 to $500,000 |
July 12 5 tornadoes
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| July 12 | 5:50 PM CDT | F3 | Worth | 15.4 | 833 | $500,000 to $5 million | ||
| July 12 | 6:15 PM CDT | F4 | Howard | 10.9 | 1,320 | 8 | $500,000 to $5 million | |
| July 12 | 7:30 PM CDT | F2 | Fayette | 6.4 | 100 | $50,000 to $500,000 | ||
| July 12 | 8:00 PM CDT | F2 | Bremer | 0.1 | 100 | $50,000 to $500,000 | ||
| July 12 | 10:10 PM CDT | F3 | Delaware | 0.1 | 833 | 2 | $500,000 to $5 million |
October 1 1 tornado
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| October 1 | 2:55 PM CDT | F3 | O'Brien | 11.2 | 10 | $50,000 to $500,000 |
Nearby
Every tornado in Iowa since 1950Warnings in force in IowaThe live radar over Iowa
What this means
Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.