Tornado and Flash Flooding in Illinois, May 16 to 17, 1999

Name: Tornado and Flash Flooding in Illinois, May 16 to 17, 1999
Start: 1999-05-16T20:00
End: 1999-05-17T07:58
Location: Illinois

May 16 to 17, 1999 · NWS DVN · 18 events in 7 counties and zones

Where it happened

Every event with a place to put it; 7 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: 1
Property damage: $186,000
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.

What happened

The episode as NWS DVN wrote it up.

Summary of events of May 16-17, 1999:On the 16th into the 17th two lines of thunderstorms developed: one north to south across western Iowa and the other repeatedly developed east to west from Butler to Clayton counties in northeast Iowa and moved east into northwest Illinois as a squall line. Thunderstorms along this line strengthened as they moved east, with several storms producing large hail, funnel clouds, damaging winds, flash flooding, and one confirmed tornado.The tornado (an F0) was spotted near Menominee in Jo Daviess County. hail as large as golf balls fell in East Dubuque (also in Jo Daviess County). Severe thunderstorm winds caused structural damage across portions of Stephenson, Whiteside, Carroll, Henry, and Bureau Counties. The costliest and most dramatic damage, however, did not come from tornadoes or hail but rather from flash flooding. Several inches of rain fell over portions of East Dubuque in only a few hours, causing a major flash flood in downtown. Water flowed down a street and into the Mississippi River, ripping up pavement and washing away cars as it went. See preceding individual Storm Data entries for further details and additional reports.

The radar

The Quad Cities radar (KDVN), 97 km away, was scanning. The volume nearest the first event began at 02:02 UTC.

Open the radar archive at this moment

Event by event

9 thunderstorm wind, 3 funnel cloud, 2 flash flood, 2 flood, 1 hail, 1 tornado. Local standard time, as filed.

Hail, Jo Daviess

When: May 16, 8:00 PM CST
Where: Jo Daviess County, East Dubuque
Measured: 1.75 in hail
Reported by: UNKNOWN
Coordinates: 42.480, -90.630

Tornado, Jo Daviess

When: May 16, 8:00 PM CST
Where: Jo Daviess County, Menominee
Rating: F0
Path length: 0.1 mi
Path width: 10 yd
Reported by: UNKNOWN
Coordinates: 42.420, -90.530

Flash Flood, Jo Daviess

When: May 16, 10:00 PM CST to May 17, 12:00 AM CST
Where: Jo Daviess County, East Dubuque
Reported by: UNKNOWN
Coordinates: 42.366, -90.212 (the zone’s center; the record gives no point)

Water 2 to 3 feet deep flowed down Wisconsin Avenue, which ironically had been under construction for a storm-drainage system. The flash flooding left 10-15-foot crevices in the road. Basements of many businesses were filled with water, and about 100 homes were evacuated during the early morning hours. The flash flooding washed away more than a dozen cars in East Dubuque. One truck was pushed into a train bridge, forcing the fast-water rescue of its driver and a passenger.

Flash Flood, Jo Daviess

When: May 16, 10:59 PM CST
Where: Jo Daviess County, East Dubuque
Reported by: UNKNOWN
Coordinates: 42.366, -90.212 (the zone’s center; the record gives no point)

Portions of the lower flats were evacuated due to flooding. Bridges on Menominee Road and North Apple Canyon Lake Road #1 were under water.

Funnel Cloud, Whiteside

When: May 16, 11:01 PM CST
Where: Whiteside County, Fulton
Reported by: UNKNOWN
Coordinates: 41.756, -89.914 (the zone’s center; the record gives no point)

Thunderstorm Wind, Stephenson

When: May 16, 11:05 PM CST
Where: Stephenson County, Freeport
Property damage: $8,000
Reported by: NEWSPAPER
Coordinates: 42.280, -89.620

Severe thunderstorm winds downed 8 trees and a traffic signal.

Thunderstorm Wind, Whiteside

When: May 16, 11:10 PM CST
Where: Whiteside County, Fulton
Property damage: $500
Reported by: UNKNOWN
Coordinates: 41.870, -90.170

Trees were downed by severe thunderstorm winds.

Thunderstorm Wind, Carroll

When: May 16, 11:15 PM CST
Where: Carroll County, Shannon
Property damage: $90,000
Reported by: NEWSPAPER
Coordinates: 42.150, -89.730

Severe thunderstorm winds first blew apart a hog shed, which caused power lines to fall onto a barn. The barn and about 400 head of hog were lost in the resulting fire.

Thunderstorm Wind, Stephenson

When: May 16, 11:25 PM CST to 11:30 PM CST
Where: Stephenson County, Orangeville
Injuries: 1 direct, 0 indirect
Property damage: $40,000
Reported by: NEWSPAPER
Coordinates: 42.470, -89.630

Severe thunderstorm winds rolled a mobile home trailer over and destroyed it. The occupant of the trailer suffered 2 dislocated shoulders, cuts, and abrasions.

Thunderstorm Wind, Stephenson

When: May 16, 11:30 PM CST
Where: Stephenson County, Freeport to Cedarville
Property damage: $15,000
Reported by: UNKNOWN
Coordinates: 42.280, -89.620

Severe thunderstorm winds downed trees and power lines from Freeport through Cedarville to Rock Grove, including several at the Cedarville Cemetery. Some trees fell onto and blocked Highway 26. At the Dornink Airport in rural Cedarville, 2 hangars were destroyed and a third hangar lost its roof.

Funnel Cloud, Whiteside

When: May 16, 11:30 PM CST
Where: Whiteside County, 7 mi NW of Morrison
Reported by: UNKNOWN
Coordinates: 41.756, -89.914 (the zone’s center; the record gives no point)

Funnel Cloud, Whiteside

When: May 16, 11:30 PM CST
Where: Whiteside County, Morrison
Reported by: UNKNOWN
Coordinates: 41.756, -89.914 (the zone’s center; the record gives no point)

Thunderstorm Wind, Henry

When: May 16, 11:45 PM CST
Where: Henry County, Annawan
Property damage: $7,000
Reported by: NEWSPAPER
Coordinates: 41.400, -89.920

Severe thunderstorm winds lifted a machine shed and tossed it between a house and garage, destroying the shed.

Thunderstorm Wind, Whiteside

When: May 16, 11:45 PM CST
Where: Whiteside County, Fulton
Property damage: $500
Reported by: UNKNOWN
Coordinates: 41.870, -90.170

Severe winds downed trees.

Thunderstorm Wind, Whiteside

When: May 16, 11:50 PM CST
Where: Whiteside County, Tampico
Property damage: $5,000
Reported by: UNKNOWN
Coordinates: 41.630, -89.780

Severe thunderstorm winds caused plaster to fall inside a home and heavily damaged a garage.

Thunderstorm Wind, Bureau

When: May 17, 12:15 AM CST
Where: Bureau County, Princeton
Measured: 71 kt (82 mph)
Property damage: $20,000
Reported by: UNKNOWN
Coordinates: 41.370, -89.470

Severe winds downed numerous trees and damaged a large storage building. A few other buildings were also damaged by falling trees.

Flood, McDonough

When: May 17, 7:50 AM CST
Where: McDonough County, Bardolph
Reported by: UNKNOWN
Coordinates: 40.456, -90.678 (the zone’s center; the record gives no point)

Highway 67 was under water and Route 9 was reported flooded.

Flood, McDonough

When: May 17, 7:58 AM CST
Where: McDonough County, Macomb
Reported by: NEWSPAPER
Coordinates: 40.456, -90.678 (the zone’s center; the record gives no point)

Twelve cars stalled in water up to 18 inches deep.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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.
Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.
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.
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 Illinois in 1999 Every state in 1999 This day in weather history The tornado archive for Illinois, 1999 Warnings in Illinois, 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: 5715216, 5715217, 5709949, 5715218, 5715219, 5710051, 5715220, 5710052, 5710053, 5715221, 5715222, 5715223, 5710054, 5715224, 5715225, 5715226, 5709950, 5710050.