Tornadoes and Hail in Iowa, May 31, 1971

Name: Tornadoes and Hail in Iowa, May 31, 1971
Start: 1971-05-31T13:15
End: 1971-05-31T22:45
Location: Iowa

May 31, 1971 · 18 events in 12 counties and zones

9 hail, 8 tornado, 1 thunderstorm wind, as filed by the National Weather Service.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $1.0 million
Crop damage: None recorded
Events: 18

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

Event by event

9 hail, 8 tornado, 1 thunderstorm wind. Local standard time, as filed.

Tornado, O'Brien

When: May 31, 1:15 PM CST
Where: O'Brien County
Rating: F3
Path length: 36.5 mi
Path width: 100 yd
Coordinates: 43.220, -95.950

Tornado, Osceola

When: May 31, 1:20 PM CST
Where: Osceola County
Rating: F3
Path length: 8.6 mi
Path width: 250 yd
Property damage: $250,000
Coordinates: 43.330, -95.530

Hail, Dickinson

When: May 31, 2:00 PM CST
Where: Dickinson County
Measured: 2 in hail
Coordinates: 43.500, -95.080

Tornado, Dickinson

When: May 31, 2:05 PM CST
Where: Dickinson County
Rating: F3
Path length: 8 mi
Path width: 200 yd
Property damage: $250,000
Coordinates: 43.370, -95.320

Hail, Winnebago

When: May 31, 4:30 PM CST
Where: Winnebago County
Measured: 2.5 in hail
Coordinates: 43.500, -93.780

Hail, Hardin

When: May 31, 5:00 PM CST
Where: Hardin County
Measured: 2.75 in hail
Coordinates: 42.500, -93.280

Tornado, Hardin

When: May 31, 5:15 PM CST
Where: Hardin County
Rating: F2
Path length: 4.5 mi
Path width: 300 yd
Property damage: $250,000
Coordinates: 42.550, -93.030

Hail, Grundy

When: May 31, 5:45 PM CST
Where: Grundy County
Measured: 3 in hail
Coordinates: 42.500, -92.780

Thunderstorm Wind, Grundy

When: May 31, 5:45 PM CST
Where: Grundy County
Coordinates: 42.500, -92.780

Tornado, Grundy

When: May 31, 6:20 PM CST
Where: Grundy County
Rating: F1
Path length: 2.3 mi
Path width: 200 yd
Coordinates: 42.450, -92.770

Tornado, Grundy

When: May 31, 6:20 PM CST
Where: Grundy County
Rating: F1
Path length: 2.3 mi
Path width: 200 yd
Coordinates: 42.450, -92.770

Tornado, Black Hawk

When: May 31, 6:30 PM CST
Where: Black Hawk County
Rating: F2
Path length: 1 mi
Path width: 200 yd
Property damage: $25,000
Coordinates: 42.400, -92.450

Tornado, Tama

When: May 31, 7:30 PM CST
Where: Tama County
Rating: F3
Path length: 9.4 mi
Path width: 600 yd
Property damage: $250,000
Coordinates: 42.100, -92.300

Hail, Benton

When: May 31, 8:15 PM CST
Where: Benton County
Measured: 3 in hail
Coordinates: 42.200, -92.000

Hail, Cedar

When: May 31, 9:00 PM CST
Where: Cedar County
Measured: 3 in hail
Coordinates: 41.880, -91.280

Hail, Van Buren

When: May 31, 9:45 PM CST
Where: Van Buren County
Measured: 2 in hail
Coordinates: 40.700, -92.000

Hail, Johnson

When: May 31, 9:45 PM CST
Where: Johnson County
Measured: 2 in hail
Coordinates: 41.700, -91.580

Hail, Johnson

When: May 31, 10:45 PM CST
Where: Johnson County
Measured: 2 in hail
Coordinates: 41.500, -91.400

What these are

Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Iowa in 1971 Every state in 1971 This day in weather history The tornado archive for Iowa, 1971

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 10012385, 10012386, 10012387, 10012388, 10012389, 10012390, 10012391, 10012392, 10012393, 10012394, 10012395, 10012396, 10012397, 10012398, 10012399, 10012400, 10012401, 10012402.