Scattered thunderstorms developed across north central Iowa along an elevated convergence zone in a near tropical atmosphere.  Feed by a low level jet of 30 knots (about 35 mph), the thunderstorms evolved into a squall line that raced east southeast across eastern Iowa and northern Illinois.  Wind damage was the most common severe report with severe crop damage occurring across a large portion of Benton County, and to a lesser extent across Iowa, Linn, and Clinton Counties.  The wind combined with a large amount of cloud to ground lightning resulted in power failures across parts of eastern Iowa and took two public safety communication towers off the air.

Thunderstorm Wind in IOWA, IOWA
From 10-AUG-06 04:15:00 to 10-AUG-06 04:15:00 (CST)
Location: AMANA
Magnitude: 57 EG
Crop damage: 15K
Reported by: OTHER FEDERAL AGENCY

Several corn fields were flattened to the northwest and north of Amana in Lenox Township.

Thunderstorm Wind in LINN, IOWA
From 10-AUG-06 04:20:00 to 10-AUG-06 04:20:00 (CST)
Location: FAIRFAX
Magnitude: 57 EG
Crop damage: 15K
Reported by: OTHER FEDERAL AGENCY

Several corn fields were flattened to the west and south of Fairfax in Fairfax Township.

Heavy Rain in LINN, IOWA
From 10-AUG-06 04:15:00 to 10-AUG-06 04:45:00 (CST)
Location: CEDAR RAPIDS
Reported by: TRAINED SPOTTER

A spotter reported 1.20 inches of rain in 30 minutes.  There were numerous reports of estimated and measured wind gusts of 39 to 43 knots (45 to 50 mph) as the storms moved through the metro area.

Thunderstorm Wind in LINN, IOWA
From 10-AUG-06 04:00:00 to 10-AUG-06 04:00:00 (CST)
Location: CENTER PT
Magnitude: 50 EG
Reported by: EMERGENCY MANAGER

A hayrack was blown across a yard on its wheels.

Thunderstorm Wind in BENTON, IOWA
From 10-AUG-06 03:57:00 to 10-AUG-06 04:02:00 (CST)
Location: NORWAY
Magnitude: 62 MG
Property damage: 2K
Reported by: TRAINED SPOTTER

A measured gust of 62 knots (71 mph) with gusts to 57 knots (66 mph) when the spotter called in the report.

Thunderstorm Wind in LINN, IOWA
From 10-AUG-06 04:15:00 to 10-AUG-06 04:15:00 (CST)
Location: MARION
Magnitude: 57 EG
Reported by: TRAINED SPOTTER

A spotter reported estimated winds of 52 to 61 knots (60 to 70 mph).

Thunderstorm Wind in LINN, IOWA
From 10-AUG-06 04:16:00 to 10-AUG-06 04:16:00 (CST)
Location: MARION
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

A spotter reported estimated 48 to 52 knot (55 to 60 mph) winds at the junction of U.S. 151 & highway 13.

Thunderstorm Wind in JOHNSON, IOWA
From 10-AUG-06 04:26:00 to 10-AUG-06 04:26:00 (CST)
Location: SWISHER
Magnitude: 57 EG
Property damage: 2K
Reported by: LAW ENFORCEMENT

Sheriff department reported trees down near the intersection of Plotz Road NW & Falcon Avenue NW.

Thunderstorm Wind in BENTON, IOWA
From 10-AUG-06 04:02:00 to 10-AUG-06 04:02:00 (CST)
Location: NORWAY
Magnitude: 57 EG
Property damage: 4K
Reported by: GENERAL PUBLIC

A public report of a two foot diameter healthy maple tree split in half.  Sustained winds were estimated at 39 knots (45 mph) with multiple gusts to 57 knots (65 mph).

Thunderstorm Wind in IOWA, IOWA
From 10-AUG-06 04:20:00 to 10-AUG-06 04:20:00 (CST)
Location: AMANA
Magnitude: 57 EG
Property damage: 5K
Reported by: LAW ENFORCEMENT

Law enforcement reported trees down along Avenue T (county highway 20).

Hail in LINN, IOWA
From 10-AUG-06 04:20:00 to 10-AUG-06 04:20:00 (CST)
Location: MARION
Magnitude: 0.88 
Reported by: BROADCAST MEDIA

KCRG TV reports penny to nickel size hail at the junction of Country Home Road & Lucore Road.  Heavy rain was also reported with winds gusting to an estimated 39 knots (45 mph).

Thunderstorm Wind in BENTON, IOWA
From 10-AUG-06 04:00:00 to 10-AUG-06 04:06:00 (CST)
Location: WALFORD
Magnitude: 57 EG
Property damage: 7K
Reported by: TRAINED SPOTTER

Numerous branches were downed and trees snapped in half.

Thunderstorm Wind in CEDAR, IOWA
From 10-AUG-06 04:55:00 to 10-AUG-06 04:55:00 (CST)
Location: WEST BRANCH
Magnitude: 57 EG
Property damage: 10K
Reported by: LAW ENFORCEMENT

Sheriff department reported winds estimated at 52 to 61 knots (60 to 70 mph) with numerous trees down across the town.

Thunderstorm Wind in LINN, IOWA
From 10-AUG-06 04:43:00 to 10-AUG-06 04:43:00 (CST)
Location: VIOLA
Magnitude: 57 EG
Property damage: 4K
Reported by: DEPT OF HIGHWAYS

The secondary roads department reported trees down in the town of Viola.

Thunderstorm Wind in LINN, IOWA
From 10-AUG-06 04:40:00 to 10-AUG-06 04:40:00 (CST)
Location: SPRINGVILLE
Magnitude: 52 EG
Property damage: 4K
Reported by: UTILITY COMPANY

A utility company reported a tree blown down in town which destroyed a power pole.

Thunderstorm Wind in JOHNSON, IOWA
From 10-AUG-06 04:31:00 to 10-AUG-06 04:31:00 (CST)
Location: NORTH LIBERTY
Magnitude: 57 EG
Property damage: 5K
Reported by: LAW ENFORCEMENT

Sheriff department reported trees down along Scales Bend Road NE.

Thunderstorm Wind in JOHNSON, IOWA
From 10-AUG-06 04:43:00 to 10-AUG-06 04:43:00 (CST)
Location: IOWA CITY
Magnitude: 57 EG
Property damage: 4K
Reported by: LAW ENFORCEMENT

Sheriff department reported trees down near the intersection of Newport Road NE & Oak Ridge Trail NE.

Thunderstorm Wind in CEDAR, IOWA
From 10-AUG-06 05:01:00 to 10-AUG-06 05:11:00 (CST)
Location: LOWDEN
Magnitude: 57 EG
Property damage: 4K
Crop damage: 8K
Reported by: OFFICIAL NWS OBS.

Co-operative observer reported trees down and corn flattened on two farms southwest of town.

Thunderstorm Wind in JACKSON, IOWA
From 10-AUG-06 05:32:00 to 10-AUG-06 05:36:00 (CST)
Location: MAQUOKETA
Magnitude: 57 EG
Property damage: 2K
Reported by: TRAINED SPOTTER

A spotter reported a 7 inch diameter walnut limb down and a 9 inch diameter oak limb down.  Heavy rain of 1.10 inches was also reported.

Thunderstorm Wind in CLINTON, IOWA
From 10-AUG-06 05:40:00 to 10-AUG-06 05:45:00 (CST)
Location: DELMAR
Magnitude: 61 EG
Property damage: 5K
Reported by: LAW ENFORCEMENT

Several trees were reported down in the town.

Thunderstorm Wind in CLINTON, IOWA
From 10-AUG-06 05:31:00 to 10-AUG-06 05:44:00 (CST)
Location: ELWOOD
Magnitude: 61 EG
Crop damage: 40K
Reported by: OTHER FEDERAL AGENCY

A large amount of corn was flattened from the Jackson/Clinton line to Delmar.  The southern extent of the crop damage was highway 136 between Elwood and Delmar.

Thunderstorm Wind in JACKSON, IOWA
From 10-AUG-06 05:31:00 to 10-AUG-06 05:35:00 (CST)
Location: MAQUOKETA
Magnitude: 57 EG
Property damage: 2K
Crop damage: 1K
Reported by: OFFICIAL NWS OBS.

Co-operative observer reported 6 inch diameter limbs down with the power out along with 1.13 inches of rain.

Thunderstorm Wind in JACKSON, IOWA
From 10-AUG-06 05:31:00 to 10-AUG-06 05:37:00 (CST)
Location: MAQUOKETA
Magnitude: 61 EG
Property damage: 8K
Crop damage: 12K
Reported by: OFFICIAL NWS OBS.

Co-operative observer reported 3 foot diameter trees down and two power poles snapped south of his farm.  A considerable amount of corn was flattened with damage to some buildings.  Time estimated based on radar.

Thunderstorm Wind in CLINTON, IOWA
From 10-AUG-06 05:36:00 to 10-AUG-06 05:40:00 (CST)
Location: DELMAR
Magnitude: 61 EG
Property damage: 5K
Reported by: LAW ENFORCEMENT

A stopped semi was blown over near the junction of highway 136 & U.S. 61.

Thunderstorm Wind in JACKSON, IOWA
From 10-AUG-06 05:48:00 to 10-AUG-06 05:48:00 (CST)
Location: PRESTON
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

A spotter reported estimated 48 to 52 knot (55 to 60 mph) winds.

Thunderstorm Wind in CLINTON, IOWA
From 10-AUG-06 05:52:00 to 10-AUG-06 05:57:00 (CST)
Location: CLINTON
Magnitude: 57 EG
Property damage: 3K
Reported by: LAW ENFORCEMENT

City police reported trees down on the west side of town.

Lightning in BENTON, IOWA
From 10-AUG-06 03:35:00 to 10-AUG-06 03:50:00 (CST)
Location: VINTON
Property damage: .5K
Reported by: NEWSPAPER

A probable lightning strike took down a tree in Vinton.

Thunderstorm Wind in BENTON, IOWA
From 10-AUG-06 03:37:00 to 10-AUG-06 03:45:00 (CST)
Location: VAN HORNE
Magnitude: 61 EG
Property damage: 3K
Reported by: EMERGENCY MANAGER

Numerous small to large trees were reported down across the town.  Time estimated based on radar.

Thunderstorm Wind in BENTON, IOWA
From 10-AUG-06 03:37:00 to 10-AUG-06 04:10:00 (CST)
Location: COUNTYWIDE
Magnitude: 61 EG
Crop damage: 15.1M
Reported by: OTHER FEDERAL AGENCY

Severe straight line winds estimated around 61 knots (70 mph) began in the western part of the county southwest of Garrison and moved across the southern third to 40 percent of the county affecting about 160 square miles.  According to official estimates, about 46,100 acres of corn was flattened with damage to about 5,100 acres of soybeans.

Thunderstorm Wind in JONES, IOWA
From 10-AUG-06 04:50:00 to 10-AUG-06 05:00:00 (CST)
Location: AMBER
Magnitude: 57 EG
Property damage: 5K
Reported by: TRAINED SPOTTER

A spotter reported a 12 inch diameter older tree down with numerous 4 inch plus diameter limbs down.  Time estimated based on radar.

Thunderstorm Wind in CLINTON, IOWA
From 10-AUG-06 05:42:00 to 10-AUG-06 05:42:00 (CST)
Location: DEWITT
Magnitude: 52 EG
Reported by: NWS EMPLOYEE(OFF DUTY)