After an early morning flash flood event in eastern Iowa, with some damaging winds near the Mississippi River, a line of slow moving supercell thunderstorms moved southeast from northern Iowa, into portions of eastern Iowa the evening of June 9th. Damaging winds, large hail, a few tornadoes, and torrential rain accompanied the storms.  This event brought flash flooding, and led to some minor to moderate river flooding on the Cedar, Iowa, and Wapsipinicon Rivers.

Hail in IOWA, IOWA
From 09-JUN-18 05:36:00 to 09-JUN-18 05:36:00 (CST-6)
Location: MARENGO
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LINN, IOWA
From 09-JUN-18 07:45:00 to 09-JUN-18 07:45:00 (CST-6)
Location: CEDAR RAPIDS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail was reported to be a mix of pea to quarter size.

Thunderstorm Wind in CLINTON, IOWA
From 09-JUN-18 03:40:00 to 09-JUN-18 03:40:00 (CST-6)
Location: FOLLETTS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A 10 inch diameter tree branch was split. The early morning storm damage time was estimated from radar.

Thunderstorm Wind in CLINTON, IOWA
From 09-JUN-18 03:40:00 to 09-JUN-18 03:40:00 (CST-6)
Location: LOW MOOR
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A large cottonwood tree around three feet in diameter was snapped off about halfway up, with the top laying on a the roof of a house near the Camanche Marina. The early morning storm damage time was estimated from radar.

Thunderstorm Wind in BENTON, IOWA
From 09-JUN-18 20:34:00 to 09-JUN-18 20:34:00 (CST-6)
Location: WATKINS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tree limbs were blown down in Watkins. The storm damage time was estimated from radar.

Thunderstorm Wind in DELAWARE, IOWA
From 09-JUN-18 21:09:00 to 09-JUN-18 21:09:00 (CST-6)
Location: MANCHESTER
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Multiple trees were snapped off about halfway up on the trunk along Highway 13 north of Manchester. The time was estimated from radar.

Thunderstorm Wind in SCOTT, IOWA
From 09-JUN-18 23:10:00 to 09-JUN-18 23:10:00 (CST-6)
Location: ELDRIDGE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A tree limb was down.

Flash Flood in LINN, IOWA
From 09-JUN-18 08:00:00 to 09-JUN-18 12:00:00 (CST-6)
Location: CEDAR RAPIDS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Urban street flooding was reported along Grande Avenue.

Flash Flood in DELAWARE, IOWA
From 09-JUN-18 22:09:00 to 09-JUN-18 23:30:00 (CST-6)
Location: MANCHESTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Water was about one foot deep over the road on the north side of Manchester.  The water was over the curbs of the road, and into the grass.

Hail in JOHNSON, IOWA
From 09-JUN-18 08:22:00 to 09-JUN-18 08:22:00 (CST-6)
Location: CORALVILLE RESV
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in CLINTON, IOWA
From 09-JUN-18 03:29:00 to 09-JUN-18 03:29:00 (CST-6)
Location: CLINTON MUNI ARPT
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The wind was measured at the Clinton Municipal Airport.

Thunderstorm Wind in BUCHANAN, IOWA
From 09-JUN-18 19:35:00 to 09-JUN-18 19:35:00 (CST-6)
Location: INDEPENDENCE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

No tree damage was reported.

Thunderstorm Wind in BENTON, IOWA
From 09-JUN-18 20:20:00 to 09-JUN-18 20:20:00 (CST-6)
Location: SHELLSBURG
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public estimated 70 mph winds with quarter size hail.

Thunderstorm Wind in BUCHANAN, IOWA
From 09-JUN-18 20:50:00 to 09-JUN-18 20:50:00 (CST-6)
Location: WINTHROP
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in BUCHANAN, IOWA
From 09-JUN-18 21:00:00 to 09-JUN-18 21:00:00 (CST-6)
Location: MONTI
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotters estimated 64 mph winds.

Hail in BUCHANAN, IOWA
From 09-JUN-18 19:49:00 to 09-JUN-18 19:49:00 (CST-6)
Location: INDEPENDENCE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The hail was mostly penny size, with a few the size of nickels.

Flash Flood in CLINTON, IOWA
From 09-JUN-18 03:15:00 to 09-JUN-18 03:15:00 (CST-6)
Location: CHARLOTTE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The mayor of Charlotte Iowa reported flash flooding of creeks in town.

Flash Flood in JACKSON, IOWA
From 09-JUN-18 04:00:00 to 09-JUN-18 04:00:00 (CST-6)
Location: SPRAGUEVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Deep Creek west of Preston was out of its banks, flowing over 17th St and closing the road.

Thunderstorm Wind in LINN, IOWA
From 09-JUN-18 21:46:00 to 09-JUN-18 21:46:00 (CST-6)
Location: MIDWAY
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Local broadcast media relayed a public report of winds around 70 mph.

Flash Flood in BUCHANAN, IOWA
From 09-JUN-18 20:48:00 to 10-JUN-18 01:00:00 (CST-6)
Location: FAIRBANK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Widespread flash flooding began in Buchanan county near Independence, with low lying areas flooded and some road closures on the east side of Independence. Flooding of gravel roads was reported about 1030 PM, 3 miles south of the Winthrop Golf Course. At 1128 PM, flash flooding caused multiple road closures in northern Buchanan county.

Flash Flood in JACKSON, IOWA
From 09-JUN-18 06:30:00 to 09-JUN-18 06:30:00 (CST-6)
Location: OTTER CREEK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Farmer's Creek was out of its banks, flowing over 175th Ave and closing the road.

Hail in SCOTT, IOWA
From 09-JUN-18 04:00:00 to 09-JUN-18 04:00:00 (CST-6)
Location: PANORAMA PARK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BUCHANAN, IOWA
From 09-JUN-18 20:02:00 to 09-JUN-18 20:02:00 (CST-6)
Location: INDEPENDENCE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in BUCHANAN, IOWA
From 09-JUN-18 20:18:00 to 09-JUN-18 20:18:00 (CST-6)
Location: INDEPENDENCE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BENTON, IOWA
From 09-JUN-18 20:24:00 to 09-JUN-18 20:24:00 (CST-6)
Location: NORWAY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

This report was relayed to the NWS by the Benton County emergency manager.

Tornado in BUCHANAN, IOWA
From 09-JUN-18 20:36:00 to 09-JUN-18 20:37:00 (CST-6)
Location: MONTI
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

An EF-1 tornado touched down southeast of Winthrop, Iowa.  A house was damaged and the garage door failed, which allowed the roof to come off. Nearby tree damage was also surveyed.

Hail in JONES, IOWA
From 09-JUN-18 05:50:00 to 09-JUN-18 05:50:00 (CST-6)
Location: FAIRVIEW
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer