Flash Flood and Flooding in Iowa, June 20, 1998

Name: Flash Flood and Flooding in Iowa, June 20, 1998
Start: 1998-06-20T12:00
End: 1998-06-20T23:00
Location: Iowa

June 20, 1998 · NWS DMX · 16 events in 12 counties and zones

A cold front to the west of Iowa moved into the state during the day. Initially, the airmass was quite capped and thunderstorms had a hard time getting going.

Where it happened

Every event with a place to put it; 14 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: $112,000
Events: 16

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.

A cold front to the west of Iowa moved into the state during the day. Initially, the airmass was quite capped and thunderstorms had a hard time getting going. Thunderstorms formed on the north edge of the cap over Minnesota, with the tail end of the storms reaching into north central Iowa. There was very little severe weather associated with the storms in Iowa. Heavy rain was the major concern as the ground was already saturated over a large part of the state. Heavy rain of 3 to 5 inches fell over north central Iowa. Five inches of rain was recorded in Scarville, in Winnebago County. Flash flooding was reported around the county with several roads flooded. The line of thunderstorms became more widespread during the later afternoon hours. Rainfall amounts of 2 to 4 inches in a two hour timeframe were reported over a several county area. The city of Iowa Falls reported 4.33 inches of rainfall in about two hours time. Urban flooding was reported over several counties from central into northeast Iowa. The only severe reports were from relatively small hail. Three quarter inch diameter hail fell in Story County at Ames, and north of Lake Mills in Winnebago County.

The radar

The Minneapolis radar (KMPX), 164 km away, was scanning. The volume nearest the first event began at 23:34 UTC.

Open the radar archive at this moment

Event by event

13 flood, 2 hail, 1 flash flood. Local standard time, as filed.

Flash Flood, Winnebago

When: June 20, 12:00 PM CST to 4:00 PM CST
Where: Winnebago County, Scarville
Property damage: $150,000
Crop damage: $15,000
Coordinates: 43.378, -93.734 (the zone’s center; the record gives no point)

Flood, Worth

When: June 20, 2:00 PM CST to 6:00 PM CST
Where: Worth County, Northwood
Property damage: $75,000
Crop damage: $10,000
Coordinates: 43.377, -93.261 (the zone’s center; the record gives no point)

Flood, Cerro Gordo

When: June 20, 2:00 PM CST to 6:00 PM CST
Where: Cerro Gordo County, Mason City
Property damage: $150,000
Crop damage: $10,000
Coordinates: 43.082, -93.261 (the zone’s center; the record gives no point)

Flood, Hancock

When: June 20, 2:00 PM CST to 6:00 PM CST
Where: Hancock County, Kanawha
Property damage: $75,000
Crop damage: $10,000
Coordinates: 43.082, -93.734 (the zone’s center; the record gives no point)

Flood, Wright

When: June 20, 2:00 PM CST to 6:00 PM CST
Where: Wright County, Clarion
Property damage: $75,000
Crop damage: $10,000
Reported by: NEWSPAPER
Coordinates: 42.733, -93.735 (the zone’s center; the record gives no point)

Flood, Butler

When: June 20, 4:15 PM CST to 7:30 PM CST
Where: Butler County, New Hartford
Property damage: $50,000
Crop damage: $5,000
Coordinates: 42.732, -92.790 (the zone’s center; the record gives no point)

Flood, Black Hawk

When: June 20, 4:15 PM CST to 7:30 PM CST
Where: Black Hawk County, Waterloo
Property damage: $75,000
Crop damage: $5,000
Coordinates: 42.470, -92.309 (the zone’s center; the record gives no point)

Flood, Bremer

When: June 20, 4:15 PM CST to 7:30 PM CST
Where: Bremer County, Waverly
Property damage: $50,000
Crop damage: $5,000
Coordinates: 42.775, -92.318 (the zone’s center; the record gives no point)

Flood, Cerro Gordo

When: June 20, 4:15 PM CST to 7:30 PM CST
Where: Cerro Gordo County, Mason City
Property damage: $50,000
Crop damage: $5,000
Coordinates: 43.082, -93.261 (the zone’s center; the record gives no point)

Flood, Franklin

When: June 20, 4:15 PM CST to 11:00 PM CST
Where: Franklin County, Hampton
Property damage: $100,000
Crop damage: $15,000
Coordinates: 42.733, -93.262 (the zone’s center; the record gives no point)

Flood, Grundy

When: June 20, 4:15 PM CST to 7:30 PM CST
Where: Grundy County, Grundy Center
Property damage: $50,000
Crop damage: $5,000
Coordinates: 42.402, -92.791 (the zone’s center; the record gives no point)

Flood, Hancock

When: June 20, 4:15 PM CST to 7:30 PM CST
Where: Hancock County, Britt
Property damage: $50,000
Crop damage: $5,000
Coordinates: 43.082, -93.734 (the zone’s center; the record gives no point)

Hail, Story

When: June 20, 5:37 PM CST
Where: Story County, Ames
Measured: 0.75 in hail
Crop damage: $1,000
Coordinates: 42.030, -93.620

Flood, Hardin

When: June 20, 7:00 PM CST to 11:00 PM CST
Where: Hardin County, Iowa Falls
Property damage: $70,000
Crop damage: $5,000
Coordinates: 42.384, -93.240 (the zone’s center; the record gives no point)

Flood, Story

When: June 20, 7:00 PM CST to 11:00 PM CST
Where: Story County, Ames
Property damage: $70,000
Crop damage: $5,000
Coordinates: 42.036, -93.465 (the zone’s center; the record gives no point)

Hail, Winnebago

When: June 20, 7:15 PM CST
Where: Winnebago County, 2 mi N of Lake Mills
Measured: 0.8 in hail
Crop damage: $1,000
Coordinates: 43.450, -93.530

What these are

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.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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 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: 5652487, 5652488, 5652489, 5652490, 5652502, 5652491, 5652492, 5652493, 5652494, 5652495, 5652496, 5652497, 5652500, 5652498, 5652499, 5652501.