Tornadoes and Flash Flood in Iowa, June 27 to 28, 1998

Name: Tornadoes and Flash Flood in Iowa, June 27 to 28, 1998
Start: 1998-06-27T17:30
End: 1998-06-28T01:00
Location: Iowa

June 27 to 28, 1998 · NWS DMX · 39 events in 21 counties and zones

Where it happened

Every event with a place to put it; 9 filed by county or forecast zone are drawn at its center, in a lighter ring. 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: $1.1 million
Crop damage: $185,000
Events: 39

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.

What happened

The episode as NWS DMX wrote it up.

Iowa was located in the warm sector of a developing storm system to the west. The warm front had moved to the northern Iowa border during the afternoon of the 27th with dew point temperatures in the mid 70s to around 80 blanketing the state in the warm sector. Initially, the airmass was capped, preventing thunderstorms from forming during the afternoon. Slightly cooler air moved in during the evening hours. In addition to the slightly cooler air moving in aloft, a cold front was poised over eastern Nebraska ready to move east into the state. Thunderstorms erupted rapidly by early evening with hail and high winds reported over northern Iowa. There were numerous reports of hail of an inch or larger in diameter, with a few reports of golf ball size hail. High winds were also a problem with many of the storms producing 60 to 70 MPH wind gusts. Reports of tree and power line damage were widespread. There were a few tornadoes as well. One tracked across open country in Cerro Gordo County before damaging a house south of Clear Lake. Another tornado touched down near Swaledale in Cerro Gordo County and passed southeast of Mason City. Much of the track was over open country, however one house was destroyed near Swaledale by this tornado. The longest track tornado moved across Butler and Bremer Counties. It also passed through open country, causing damage to crops and out buildings. In addition to these, there were a few brief touchdowns reported. Iowa soil remained very saturated with numerous rivers at or near flood stage. Heavy rainfall of near 4 inches in a couple hours time caused flash flooding in Cerro Gordo County. A widespread area of north central into northeast Iowa received heavy rainfall. Many areas picked up two to four inches of rain in a few hour period. This resulted in urban and small stream flooding, and ultimately general river flooding in the days that followed. As the storms moved through Worth County, lightning struck an outbuilding west of Kensett. The building was set on fire and destroyed.

The radar

The Minneapolis radar (KMPX), 153 km away, was scanning. The volume nearest the first event began at 23:27 UTC.

Open the radar archive at this moment

Event by event

20 thunderstorm wind, 7 flood, 5 hail, 5 tornado, 1 lightning, 1 flash flood. Local standard time, as filed.

Thunderstorm Wind, Winnebago

When: June 27, 5:30 PM CST
Where: Winnebago County, 7 mi NE of Lake Mills
Measured: 65 kt (75 mph)
Property damage: $150,000
Crop damage: $30,000
Reported by: NEWSPAPER
Coordinates: 43.480, -93.430

Hail, Hancock

When: June 27, 5:39 PM CST
Where: Hancock County, 5 mi N of Britt
Measured: 1 in hail
Property damage: $500
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 43.170, -93.820

Hail, Winnebago

When: June 27, 5:59 PM CST
Where: Winnebago County, Forest City
Measured: 0.75 in hail
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 43.270, -93.650

Thunderstorm Wind, Worth

When: June 27, 6:05 PM CST
Where: Worth County, Northwood
Measured: 52 kt (60 mph)
Property damage: $3,000
Reported by: UNKNOWN
Coordinates: 43.450, -93.220

Lightning, Worth

When: June 27, 6:15 PM CST
Where: Worth County, 5 mi W of Kensett
Property damage: $20,000
Reported by: NEWSPAPER
Coordinates: 43.377, -93.261 (the zone’s center; the record gives no point)

Hail, Worth

When: June 27, 6:34 PM CST
Where: Worth County, 2 mi N of Manly
Measured: 1.25 in hail
Property damage: $1,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 43.320, -93.200

Hail, Worth

When: June 27, 6:40 PM CST
Where: Worth County, 2 mi SW of Manly
Measured: 1 in hail
Property damage: $500
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 43.270, -93.230

Tornado, Cerro Gordo

When: June 27, 6:46 PM CST to 6:57 PM CST
Where: Cerro Gordo County, Thornton to 4 mi S of Clear Lake
Rating: F2
Path length: 7.5 mi
Path width: 50 yd
Property damage: $50,000
Crop damage: $2,000
Reported by: UNKNOWN
Coordinates: 42.980, -93.430

Tornado, Cerro Gordo

When: June 27, 7:22 PM CST to 7:47 PM CST
Where: Cerro Gordo County, Swaledale to Mason City
Rating: F2
Path length: 12.5 mi
Path width: 50 yd
Property damage: $125,000
Crop damage: $10,000
Reported by: NEWSPAPER
Coordinates: 42.980, -93.330

Thunderstorm Wind, Cerro Gordo

When: June 27, 7:30 PM CST
Where: Cerro Gordo County, Dougherty
Measured: 56 kt (64 mph)
Property damage: $25,000
Crop damage: $2,000
Reported by: UNKNOWN
Coordinates: 42.930, -93.070

Flash Flood, Cerro Gordo

When: June 27, 7:30 PM CST to 10:30 PM CST
Where: Cerro Gordo County, Mason City
Property damage: $100,000
Crop damage: $25,000
Reported by: UNKNOWN
Coordinates: 43.082, -93.261 (the zone’s center; the record gives no point)

Thunderstorm Wind, Greene

When: June 27, 9:20 PM CST
Where: Greene County, Grand Jct
Measured: 52 kt (60 mph)
Property damage: $5,000
Reported by: NEWSPAPER
Coordinates: 42.030, -94.230

Tornado, Butler

When: June 27, 9:23 PM CST to 9:57 PM CST
Where: Butler County, Austinville to 1 mi SE of Shell Rock
Rating: F2
Path length: 20.5 mi
Path width: 75 yd
Property damage: $10,000
Crop damage: $2,000
Reported by: UNKNOWN
Coordinates: 42.580, -92.930

Thunderstorm Wind, Wright

When: June 27, 9:23 PM CST
Where: Wright County, Belmond
Measured: 61 kt (70 mph)
Property damage: $15,000
Crop damage: $1,000
Reported by: UNKNOWN
Coordinates: 42.850, -93.600

Thunderstorm Wind, Franklin

When: June 27, 9:43 PM CST
Where: Franklin County, Hampton
Measured: 56 kt (64 mph)
Property damage: $30,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.750, -93.200

Tornado, Bremer

When: June 27, 9:57 PM CST to 10:05 PM CST
Where: Bremer County, Waverly to 6 mi S of Waverly
Rating: F2
Path length: 5 mi
Path width: 75 yd
Property damage: $3,000
Crop damage: $500
Reported by: UNKNOWN
Coordinates: 42.670, -92.570

Thunderstorm Wind, Bremer

When: June 27, 10:05 PM CST
Where: Bremer County, Waverly
Measured: 56 kt (64 mph)
Property damage: $25,000
Crop damage: $1,000
Reported by: UNKNOWN
Coordinates: 42.730, -92.480

Thunderstorm Wind, Boone

When: June 27, 10:05 PM CST
Where: Boone County, 3 mi SW of Boone
Measured: 61 kt (70 mph)
Property damage: $25,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.030, -93.920

Thunderstorm Wind, Boone

When: June 27, 10:05 PM CST
Where: Boone County, Madrid
Measured: 50 kt (58 mph)
Property damage: $1,000
Reported by: UNKNOWN
Coordinates: 41.880, -93.850

Hail, Bremer

When: June 27, 10:07 PM CST
Where: Bremer County, Waverly
Measured: 1.75 in hail
Property damage: $25,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.730, -92.480

Thunderstorm Wind, Dallas

When: June 27, 10:10 PM CST
Where: Dallas County, Perry
Measured: 56 kt (64 mph)
Property damage: $5,000
Crop damage: $1,000
Reported by: UNKNOWN
Coordinates: 41.830, -94.120

Thunderstorm Wind, Story

When: June 27, 10:10 PM CST
Where: Story County, Ames
Measured: 56 kt (64 mph)
Property damage: $20,000
Crop damage: $1,000
Reported by: UNKNOWN
Coordinates: 42.030, -93.620

Thunderstorm Wind, Dallas

When: June 27, 10:13 PM CST
Where: Dallas County, Adel
Measured: 50 kt (58 mph)
Property damage: $1,000
Reported by: UNKNOWN
Coordinates: 41.620, -94.020

Thunderstorm Wind, Grundy

When: June 27, 10:30 PM CST
Where: Grundy County, Reinbeck
Measured: 52 kt (60 mph)
Property damage: $1,000
Reported by: UNKNOWN
Coordinates: 42.320, -92.600

Thunderstorm Wind, Adams

When: June 27, 10:30 PM CST
Where: Adams County, 3 mi E of Prescott
Measured: 56 kt (64 mph)
Property damage: $2,000
Reported by: UNKNOWN
Coordinates: 41.030, -94.580

Flood, Cerro Gordo

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Cerro Gordo County, Mason City
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 43.082, -93.261 (the zone’s center; the record gives no point)

Flood, Black Hawk

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Black Hawk County, Waterloo
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.470, -92.309 (the zone’s center; the record gives no point)

Flood, Bremer

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Bremer County, Waverly
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.775, -92.318 (the zone’s center; the record gives no point)

Flood, Butler

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Butler County, New Hartford
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.732, -92.790 (the zone’s center; the record gives no point)

Flood, Franklin

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Franklin County, Hampton
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.733, -93.262 (the zone’s center; the record gives no point)

Flood, Grundy

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Grundy County, Grundy Center
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.402, -92.791 (the zone’s center; the record gives no point)

Flood, Hardin

When: June 27, 10:30 PM CST to June 28, 1:00 AM CST
Where: Hardin County, Iowa Falls
Property damage: $50,000
Crop damage: $10,000
Reported by: UNKNOWN
Coordinates: 42.384, -93.240 (the zone’s center; the record gives no point)

Thunderstorm Wind, Black Hawk

When: June 27, 10:40 PM CST
Where: Black Hawk County, Waterloo
Measured: 52 kt (60 mph)
Property damage: $5,000
Reported by: UNKNOWN
Coordinates: 42.500, -92.350

Thunderstorm Wind, Marshall

When: June 27, 10:45 PM CST
Where: Marshall County, 2 mi W of State Center
Measured: 56 kt (64 mph)
Property damage: $5,000
Crop damage: $500
Reported by: UNKNOWN
Coordinates: 42.020, -93.200

Thunderstorm Wind, Marshall

When: June 27, 10:45 PM CST
Where: Marshall County, 1 mi W of State Center
Measured: 56 kt (64 mph)
Property damage: $3,000
Reported by: UNKNOWN
Coordinates: 42.020, -93.180

Thunderstorm Wind, Union

When: June 27, 10:45 PM CST
Where: Union County, Lorimor
Measured: 52 kt (60 mph)
Property damage: $25,000
Crop damage: $2,000
Reported by: UNKNOWN
Coordinates: 41.130, -94.070

Thunderstorm Wind, Jasper

When: June 27, 11:15 PM CST to 11:25 PM CST
Where: Jasper County, Monroe
Measured: 52 kt (60 mph)
Property damage: $10,000
Reported by: UNKNOWN
Coordinates: 41.520, -93.100

Tornado, Tama

When: June 27, 11:20 PM CST
Where: Tama County, Chelsea
Rating: F0
Path length: 0.1 mi
Path width: 20 yd
Reported by: UNKNOWN
Coordinates: 41.920, -92.400

Thunderstorm Wind, Poweshiek

When: June 28, 12:00 AM CST
Where: Poweshiek County, Montezuma
Measured: 56 kt (64 mph)
Property damage: $25,000
Crop damage: $2,000
Reported by: UNKNOWN
Coordinates: 41.580, -92.530

What these are

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.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Lightning: A lightning strike that killed, injured or caused damage.
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.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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

The same day elsewhere

Every storm in Iowa in 1998 Every state in 1998 This day in weather history The tornado archive for Iowa, 1998 Warnings in Iowa, June 1998

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: 5652756, 5652636, 5652637, 5652638, 5652755, 5652639, 5652640, 5652641, 5652642, 5652648, 5652746, 5652754, 5652643, 5652645, 5652646, 5652644, 5652647, 5652731, 5652740, 5652732, 5652733, 5652734, 5652737, 5652735, 5652736, 5652747, 5652748, 5652749, 5652750, 5652751, 5652752, 5652753, 5652738, 5652739, 5652741, 5652742, 5652743, 5652744, 5652745.