Strong to severe storms developed north of a stationary front across Iowa and Northern Illinois during the afternoon and evening hours.  A strong low level jet continuously pumped copious amounts of moisture over the front that resulted in heavy rain and flash flooding.  The proximity of the front allowed sufficient wind shear to be present that allowed 6 tornadoes to develop during peak heating hours across Benton, Linn, and Jones counties.  The KDVN 88D radar was taken out by a lightning strike just before 1800 CST but had estimated that close to 9 inches of rain had fallen across the Cedar Rapids metropolitan area and headwaters of Indian Creek.

Hail in BENTON, IOWA
From 21-MAY-04 15:22:00 to 21-MAY-04 15:27:00 (CST)
Location: ATKINS
Magnitude: 1.00 
Property damage: 5K
Reported by: TRAINED SPOTTER

Funnel Cloud in BENTON, IOWA
From 21-MAY-04 15:26:00 to 21-MAY-04 15:28:00 (CST)
Location: URBANA
Reported by: EMERGENCY MANAGER

Hail in LINN, IOWA
From 21-MAY-04 15:43:00 to 21-MAY-04 15:46:00 (CST)
Location: CEDAR RAPIDS
Magnitude: 1.75 
Property damage: 4K
Reported by: EMERGENCY MANAGER

On I-380

Thunderstorm Wind in BENTON, IOWA
From 21-MAY-04 15:16:00 to 21-MAY-04 15:18:00 (CST)
Location: ATKINS
Magnitude: 53 MG
Property damage: 2K
Reported by: TRAINED SPOTTER

Heavy Rain in LINN, IOWA
From 21-MAY-04 16:42:00 to 21-MAY-04 16:42:00 (CST)
Location: MARION
Reported by: EMERGENCY MANAGER

Raining at the rate of 9 inches per hour.  Nuisance flooding at the intersection of Highway 13 and Country Home Rd (E34).

Hail in JONES, IOWA
From 21-MAY-04 16:52:00 to 21-MAY-04 16:55:00 (CST)
Location: MARTELLE
Magnitude: 1.75 
Property damage: 5K
Crop damage: 5K
Reported by: TRAINED SPOTTER

Hail in CEDAR, IOWA
From 21-MAY-04 17:02:00 to 21-MAY-04 17:05:00 (CST)
Location: MECHANICSVILLE
Magnitude: 0.75 
Crop damage: 2K
Reported by: LAW ENFORCEMENT

Hail in JACKSON, IOWA
From 21-MAY-04 17:04:00 to 21-MAY-04 17:07:00 (CST)
Location: MAQUOKETA
Magnitude: 0.88 
Reported by: LAW ENFORCEMENT

North side of city

Hail in JACKSON, IOWA
From 21-MAY-04 17:04:00 to 21-MAY-04 17:07:00 (CST)
Location: MAQUOKETA
Magnitude: 1.00 
Property damage: 2K
Crop damage: 4K
Reported by: TRAINED SPOTTER

Funnel Cloud in JONES, IOWA
From 21-MAY-04 16:24:00 to 21-MAY-04 16:26:00 (CST)
Location: OLIN
Reported by: GENERAL PUBLIC

Near the Jct of Highway 38 and E45.

Hail in JONES, IOWA
From 21-MAY-04 16:24:00 to 21-MAY-04 16:27:00 (CST)
Location: MARTELLE
Magnitude: 0.88 
Crop damage: 3K
Reported by: TRAINED SPOTTER

Hail in BENTON, IOWA
From 21-MAY-04 14:43:00 to 21-MAY-04 14:45:00 (CST)
Location: VAN HORNE
Magnitude: 1.75 
Property damage: 2K
Crop damage: 4K
Reported by: TRAINED SPOTTER

Hail in BENTON, IOWA
From 21-MAY-04 14:32:00 to 21-MAY-04 14:35:00 (CST)
Location: KEYSTONE
Magnitude: 1.00 
Property damage: 3K
Reported by: TRAINED SPOTTER

Funnel Cloud in BENTON, IOWA
From 21-MAY-04 14:53:00 to 21-MAY-04 14:54:00 (CST)
Location: MT AUBURN
Reported by: EMERGENCY MANAGER

Heavy Rain in BENTON, IOWA
From 21-MAY-04 15:05:00 to 21-MAY-04 15:15:00 (CST)
Location: VINTON
Reported by: EMERGENCY MANAGER

Water ponding on highway 218

Thunderstorm Wind in LINN, IOWA
From 21-MAY-04 16:30:00 to 21-MAY-04 16:35:00 (CST)
Location: CEDAR RAPIDS
Magnitude: 55 EG
Property damage: 10K
Crop damage: 5K
Reported by: EMERGENCY MANAGER

Barns damaged with outbuildings destroyed between Cedar Rapids and Ely.

Heavy Rain in LINN, IOWA
From 21-MAY-04 16:34:00 to 21-MAY-04 16:34:00 (CST)
Location: CEDAR RAPIDS
Reported by: EMERGENCY MANAGER

Raining at the rate of 4 inches per hour at Highway 13 and Indian Creek.

Lightning in SCOTT, IOWA
From 21-MAY-04 17:58:00 to 21-MAY-04 17:58:00 (CST)
Location: DAVENPORT ARPT
Property damage: 300K
Reported by: OFFICIAL NWS OBS.

KDVN 88D taken out by lightning.

Flash Flood in BUCHANAN, IOWA
From 21-MAY-04 21:00:00 to 22-MAY-04 01:00:00 (CST)
Location: STANLEY
Property damage: 100K
Reported by: EMERGENCY MANAGER

Roads and bridges flooded out east of Stanley.  Bridge washed out and severely damaged near the intersection of Quinn Street and 100th Street.

Hail in LINN, IOWA
From 21-MAY-04 15:54:00 to 21-MAY-04 15:57:00 (CST)
Location: SPRINGVILLE
Magnitude: 1.75 
Property damage: 5K
Reported by: EMERGENCY MANAGER

Heavy Rain in LINN, IOWA
From 21-MAY-04 16:17:00 to 21-MAY-04 16:17:00 (CST)
Location: ROBINS
Reported by: GENERAL PUBLIC

Water ponding on roads

Flash Flood in LINN, IOWA
From 21-MAY-04 17:30:00 to 21-MAY-04 23:00:00 (CST)
Location: MARION
Property damage: 10K
Reported by: EMERGENCY MANAGER

Indian creek rapidly spilling out of its banks with numerous roads blocked by water in Marion and Cedar Rapids.  Four boys trapped in the football stands at the High School in Marion at 1804 CST with a swift water rescue underway.  Radar estimates of close to 9 inches of rain had fallen by 1800 CST before it was taken out by lightning.  By 2224 CST, Linn County Emergency Manager reports that Hiawatha Creek is rising rapidly with a major sandbagging effort underway along Indian Creek in Cedar Rapids.