Flash Flooding and Flood in Iowa, May 16 to 17, 1999

Name: Flash Flooding and Flood in Iowa, May 16 to 17, 1999
Start: 1999-05-16T13:58
End: 1999-05-17T01:00
Location: Iowa

May 16 to 17, 1999 · NWS DVN · 37 events in 14 counties and zones

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: 2
Property damage: $22 million
Crop damage: None recorded
Events: 37

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 DVN wrote it up.

Summary of events of May 16-17, 1999:Two lines of thunderstorms developed over Iowa: one north to south across western Iowa and moved east, and the other repeatedly developed east to west from Butler to Clayton counties in northeast Iowa and moved east. The training of thunderstorms in the northern line dropped extremely heavy rains across portions of northeast Iowa, with an unoffial rainfall total of 8 inches just north of Buchanan County. The storms produced severe weather of nearly every type, including large hail (up to the size of golf balls in Fairbank in Buchanan County), damaging winds, funnel clouds, and flash flooding. Although there were no confirmed tornadoes, it is believed that some of the thunderstorm wind damage was enhanced in some places by gustnado development along the leading edge of the squall line. The most extensive wind damage (with at least 2 minor injuries) occurred in Cedar Rapids and Walker in Linn County. Other hard-hit areas included Sigourney (Keokuk County), Washington and West Chester (Washington County), Baldwin and Miles in Jackson County, and rural Jones County near Onslow and Wyoming. Other reports of wind damage to trees and power lines came from Benton, Jones, Muscatine, and Johnson Counties. The winds also derailed a train near Lowden in Cedar County. After the widespread heavy rain, flash flooding soon developed, with the most extensive flash flooding from Buchanan county eastward across Delaware and Dubuque Counties into Jo Daviess County in Illinois. The North Fork of the Maquoketa River surged quickly out of its banks, flooding portions of Dyersville (Dubuque County). Much of Dubuque County also suffered major damage from flash flooding. (See also Storm data entries for northwest Illinois for details on the damage in East Dubuque in Jo Daviess County Illinois.)By mid-morning on the 17th, the flash flooding had turned into extensive river flooding and then eventually became a record flood on the Wapsipinicon River. See the following Flood entry for details.

The radar

The La Crosse radar (KARX), 150 km away, was scanning. The volume nearest the first event began at 19:57 UTC.

Open the radar archive at this moment

Event by event

15 thunderstorm wind, 11 flash flood, 8 hail, 2 funnel cloud, 1 flood. Local standard time, as filed.

Hail, Buchanan

When: May 16, 1:58 PM CST
Where: Buchanan County, Fairbank
Measured: 0.75 in hail
Reported by: UNKNOWN
Coordinates: 42.630, -92.050

Hail, Buchanan

When: May 16, 5:05 PM CST
Where: Buchanan County, Fairbank
Measured: 1 in hail
Reported by: UNKNOWN
Coordinates: 42.630, -92.050

Hail, Buchanan

When: May 16, 5:40 PM CST
Where: Buchanan County, Fairbank
Measured: 0.88 in hail
Reported by: UNKNOWN
Coordinates: 42.630, -92.050

Flood, Buchanan

When: May 16, 5:58 PM CST to 6:30 PM CST
Where: Buchanan County, Fairbank
Reported by: UNKNOWN
Coordinates: 42.471, -91.838 (the zone’s center; the record gives no point)

Heavy rain caused tremendous urban flooding in Fairbank, with numerous alleys and yards flooded.

Hail, Buchanan

When: May 16, 6:06 PM CST
Where: Buchanan County, Fairbank
Measured: 1.25 in hail
Reported by: UNKNOWN
Coordinates: 42.630, -92.050

Hail, Buchanan

When: May 16, 6:07 PM CST
Where: Buchanan County, Fairbank
Measured: 1.75 in hail
Reported by: UNKNOWN
Coordinates: 42.630, -92.050

Hail, Jones

When: May 16, 6:15 PM CST
Where: Jones County, 3 mi NW of Temple Hill
Measured: 0.75 in hail
Reported by: UNKNOWN
Coordinates: 42.270, -91.020

Hail, Dubuque

When: May 16, 7:55 PM CST
Where: Dubuque County, Dubuque
Measured: 1.5 in hail
Reported by: UNKNOWN
Coordinates: 42.500, -90.670

Hail, Jones

When: May 16, 8:03 PM CST
Where: Jones County, Monticello
Measured: 1 in hail
Reported by: UNKNOWN
Coordinates: 42.230, -91.200

Thunderstorm Wind, Benton

When: May 16, 9:10 PM CST
Where: Benton County, 1 mi E of Mt Auburn
Property damage: $500
Reported by: UNKNOWN
Coordinates: 42.250, -92.080

Severe thunderstorm winds downed several 30-foot trees.

Thunderstorm Wind, Johnson

When: May 16, 9:25 PM CST
Where: Johnson County, North Liberty
Property damage: $5,000
Reported by: UNKNOWN
Coordinates: 41.750, -91.620

Severe thunderstorm winds, or possibly a gustnado, uprooted a tree and damaged several others at a residence. The house sustained minor damage.

Thunderstorm Wind, Linn

When: May 16, 9:38 PM CST
Where: Linn County, Cedar Rapids
Injuries: 2 direct, 0 indirect
Property damage: $500,000
Reported by: UNKNOWN
Coordinates: 42.000, -91.650

Severe thunderstorm winds blew most of the roof off the MidAmerica Housing partnership building in northeast Cedar Rapids. Debris from the roof was blown into other buildings and interior beams were pulled away from the structure. Severe winds also blew two 18-wheel tractor-trailer trucks off Highway 380 near Center Point, causing minor injuries. In addition, at least 20 power lines were downed in the Cedar Rapids area alone.

Thunderstorm Wind, Keokuk

When: May 16, 9:48 PM CST
Where: Keokuk County, Sigourney
Measured: 71 kt (82 mph)
Property damage: $35,000
Reported by: UNKNOWN
Coordinates: 41.330, -92.200

Severe thunderstorm winds estimated at 80 mph by spotters destroyed one building and damaged others at the county fairgrounds. The roof and walls of the commercial exhibition building were torn off, scattering debris eastward into other buildings. 2x4 boards were driven into the roof of the main fair building. Damage at the fairgrounds was estimated at $30,000 to $35,000.

Thunderstorm Wind, Cedar

When: May 16, 10:00 PM CST
Where: Cedar County, 1 mi W of Lowden
Property damage: $10,000
Reported by: UNKNOWN
Coordinates: 41.850, -90.950

An empty coal train was derailed on Highway 30 between Lowden and Clarence, blocking the eastbound tracks for nearly one day.

Thunderstorm Wind, Washington

When: May 16, 10:00 PM CST
Where: Washington County, Washington
Property damage: $2,000
Reported by: NEWSPAPER
Coordinates: 41.300, -91.700

Severe winds tore the metal roof from a welding shop and blew it into a neighboring business.

Thunderstorm Wind, Johnson

When: May 16, 10:00 PM CST
Where: Johnson County, Iowa City
Property damage: $200
Reported by: NEWSPAPER
Coordinates: 41.670, -91.550

Severe thunderstorm winds downed trees.

Thunderstorm Wind, Jones

When: May 16, 10:00 PM CST
Where: Jones County, Anamosa
Property damage: $750
Reported by: NEWSPAPER
Coordinates: 42.120, -91.280

Severe thunderstorm winds downed a large tree, which fell onto a house.

Thunderstorm Wind, Washington

When: May 16, 10:05 PM CST
Where: Washington County, West Chester
Property damage: $1,000
Reported by: NEWSPAPER
Coordinates: 41.330, -91.830

Severe thunderstorm winds downed tree branches onto the roofs of at least 2 houses.

Thunderstorm Wind, Linn

When: May 16, 10:15 PM CST
Where: Linn County, Walker
Property damage: $20,000
Reported by: UNKNOWN
Coordinates: 42.280, -91.830

Severe thunderstorm winds tore the roof off a barn and damaged at least 2 houses.

Thunderstorm Wind, Muscatine

When: May 16, 10:15 PM CST
Where: Muscatine County, Muscatine
Property damage: $500
Reported by: LAW ENFORCEMENT
Coordinates: 41.420, -91.050

Severe thunderstorm winds downed power lines.

Thunderstorm Wind, Jones

When: May 16, 10:20 PM CST
Where: Jones County, 2 mi NE of Onslow
Property damage: $40,000
Reported by: NEWSPAPER
Coordinates: 42.130, -90.980

Severe thunderstorm winds caused extensive damage on a farm northeast of Onslow. On the property, a mobile home, shop, and several smaller buildings were destroyed. The barn was shifted one foot off its foundation and several pipe gates were mangled and destroyed.

Thunderstorm Wind, Jones

When: May 16, 10:20 PM CST
Where: Jones County, 2 mi SE of Wyoming
Property damage: $40,000
Reported by: NEWSPAPER
Coordinates: 42.050, -90.970

Severe thunderstorm winds destroyed a cattle shed, uprooted a large tree, overturned a feed bunk, and broke windows at a farm southeast of Wyoming. Nearby, a barn was destroyed covering the road with debris, a tree was toppled onto a house, and the roof of a shed was wrapped around a tree. Another barn was also destroyed.

Thunderstorm Wind, Jackson

When: May 16, 10:30 PM CST
Where: Jackson County, 4 mi SE of Miles
Property damage: $50,000
Reported by: NEWSPAPER
Coordinates: 42.020, -90.270

Severe thunderstorm winds caused major damage at a farm 3.5 miles southeast of Miles. The wind completely destroyed a 54'x144' machine shed, a corn crib, and extensive fencing. Numerous pieces of farm machinery were damaged. The garage was moved off its foundation, damaging the car and truck that were inside. Siding was also torn off and windows were broken at a house.

Thunderstorm Wind, Jackson

When: May 16, 10:30 PM CST
Where: Jackson County, Baldwin
Property damage: $15,000
Reported by: NEWSPAPER
Coordinates: 42.070, -90.850

Severe thunderstorm winds destroyed a machine shed, one grain bin, and one silo. Two other silos and a loading chute were also damaged.

Flash Flood, Delaware

When: May 16, 10:40 PM CST
Where: Delaware County, Manchester
Reported by: UNKNOWN
Coordinates: 42.471, -91.367 (the zone’s center; the record gives no point)

Streets and the city park were flooded.

Funnel Cloud, Scott

When: May 16, 10:50 PM CST
Where: Scott County, Long Grove
Reported by: UNKNOWN
Coordinates: 41.637, -90.623 (the zone’s center; the record gives no point)

on Route 61

Funnel Cloud, Clinton

When: May 16, 10:55 PM CST
Where: Clinton County, Folletts
Reported by: UNKNOWN
Coordinates: 41.898, -90.532 (the zone’s center; the record gives no point)

Flash Flood, Buchanan

When: May 16, 10:55 PM CST
Where: Buchanan County, Lamont
Reported by: UNKNOWN
Coordinates: 42.471, -91.838 (the zone’s center; the record gives no point)

Flooding was reported near Highway 281 and Highway 150. Flooding was also reported south of Stanley near C57 and W33. Water covered Highway 187 south of Lamont.

Flash Flood, Buchanan

When: May 16, 10:55 PM CST
Where: Buchanan County, Fairbank
Reported by: UNKNOWN
Coordinates: 42.471, -91.838 (the zone’s center; the record gives no point)

Flooding made the Fairbank Bridge impassable.

Flash Flood, Dubuque

When: May 16, 10:58 PM CST
Where: Dubuque County, Dubuque
Reported by: UNKNOWN
Coordinates: 42.469, -90.882 (the zone’s center; the record gives no point)

Flooding was reported on Paradise Valley, Herber, and Rupp Hollow Roads.

Flash Flood, Delaware

When: May 16, 11:00 PM CST
Where: Delaware County, 2 mi N of Dundee
Reported by: NEWSPAPER
Coordinates: 42.471, -91.367 (the zone’s center; the record gives no point)

Flash flooding caused the boat ramp to collapse and flooded bridges at Backbone State Park.

Flash Flood, Buchanan

When: May 16, 11:01 PM CST
Where: Buchanan County, Fairbank
Reported by: UNKNOWN
Coordinates: 42.471, -91.838 (the zone’s center; the record gives no point)

Highway 281 was closed due to flooding, and a truck dealership and restaurant were under high water.

Flash Flood, Dubuque

When: May 16, 11:30 PM CST to May 17, 1:00 AM CST
Where: Dubuque County, Dyersville
Property damage: $5.0 million
Reported by: UNKNOWN
Coordinates: 42.469, -90.882 (the zone’s center; the record gives no point)

Flash flooding along the The North Fork of the Maquoketa River caused extensive damage in Dyersville. Numerous businesses across town sustained major damage. The costliest damage occurred at Scale Models, which sustained an estimated $150,000 in damage. Other businesses reported flooding to depths of 7 feet in their basements. About 100 people were evacuated from 60 homes. State officials set the preliminary damage estimates from Dyersville at $3 to $5 million.

Flash Flood, Dubuque

When: May 17, 12:00 AM CST to 1:00 AM CST
Where: Dubuque County, Dubuque
Property damage: $16 million
Reported by: UNKNOWN
Coordinates: 42.469, -90.882 (the zone’s center; the record gives no point)

Five to six feet of water flooded city streets in downtown. Major road damage resulted, including buckled roads and pavement washed away. Approximately 25 residential blocks were affected. Basements in over 60 houses were flooded with water from 2 feet deep up to the rafters. Flooding was reported between 20th and 28th Streets and between between Washington and Jackson streets. State damage estimates were set at $17 million in Dubuque.

Flash Flood, Dubuque

When: May 17, 12:45 AM CST
Where: Dubuque County, Dubuque
Reported by: UNKNOWN
Coordinates: 42.469, -90.882 (the zone’s center; the record gives no point)

The Little Maquoketa River flooded Highway 5 north of Dubuque.

Flash Flood, Dubuque

When: May 17, 1:00 AM CST
Where: Dubuque County, Sageville
Reported by: UNKNOWN
Coordinates: 42.469, -90.882 (the zone’s center; the record gives no point)

Flooding was reported in Sageville.

Flash Flood, Dubuque

When: May 17, 1:00 AM CST
Where: Dubuque County, Durango
Reported by: UNKNOWN
Coordinates: 42.469, -90.882 (the zone’s center; the record gives no point)

Flooding was reported in Durango.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
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.
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.
Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.

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

The same day elsewhere

Every storm in Iowa in 1999 Every state in 1999 This day in weather history Warnings in Iowa, May 1999

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: 5715031, 5715032, 5715033, 5715036, 5715034, 5715035, 5715037, 5715038, 5715039, 5715040, 5715041, 5715042, 5715043, 5715044, 5715127, 5715210, 5715213, 5715128, 5715045, 5715215, 5715211, 5715212, 5715129, 5715209, 5715046, 5715116, 5715117, 5715118, 5715119, 5715120, 5715214, 5715121, 5715125, 5715122, 5715123, 5715124, 5715126.