Severe thunderstorms rapidly developed across parts of northeast Illinois during the afternoon hours of June 4th and then moved across northwest Indiana.  Several areas sustained significant wind damage.  A wind gust to 82 mph was measured in Lowell.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:15:00 to 04-JUN-11 15:17:00 (CST-6)
Location: ST JOHN
Magnitude: 65.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A semi truck was blown over.  Trees two to three feet in diameter were blown down.  Tops of pine trees were also blown off.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:37:00 to 04-JUN-11 15:37:00 (CST-6)
Location: NORTH HAYDEN
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A wind gust to 70 mph was estimated near White Oak and 181st Avenues.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:39:00 to 04-JUN-11 15:39:00 (CST-6)
Location: NORTH HAYDEN
Magnitude: 61.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A billboard and a 40 foot tall tree were blown down near Route 41 and Route 2.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:44:00 to 04-JUN-11 15:44:00 (CST-6)
Location: LOWELL
Magnitude: 71.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in NEWTON, INDIANA
From 04-JUN-11 16:58:00 to 04-JUN-11 16:59:00 (CST-6)
Location: KENTLAND
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in BENTON, INDIANA
From 04-JUN-11 18:16:00 to 04-JUN-11 18:17:00 (EST-5)
Location: EARL PARK
Magnitude: 68.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A wind gust to 78 mph was measured in Earl Park.  Several trees were blown down or uprooted including a 30 inch diameter tree that was snapped off 3 feet from its base.

Thunderstorm Wind in BENTON, INDIANA
From 04-JUN-11 18:33:00 to 04-JUN-11 18:38:00 (EST-5)
Location: BOSWELL
Magnitude: 65.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Numerous trees and power lines were blown down across southern Benton County.

Thunderstorm Wind in PORTER, INDIANA
From 04-JUN-11 15:50:00 to 04-JUN-11 15:53:00 (CST-6)
Location: HEBRON
Magnitude: 65.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Route 2 from Lake County into Porter County was impassable due to numerous trees and utility poles blown down.  As many as 60 trees were either damaged or blown down in Hebron.  Trees and structures were damaged along 900S.

Thunderstorm Wind in JASPER, INDIANA
From 04-JUN-11 15:56:00 to 04-JUN-11 15:56:00 (CST-6)
Location: DEMOTTE
Magnitude: 65.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Grain bins and an outbuilding were destroyed northwest of De Motte.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:38:00 to 04-JUN-11 15:38:00 (CST-6)
Location: CROWN PT
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Large trees were blown down south of Crown Point near a hospital and the fairgrounds.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:41:00 to 04-JUN-11 15:41:00 (CST-6)
Location: ORCHARD GROVE
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees and signs were blown down.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:45:00 to 04-JUN-11 15:50:00 (CST-6)
Location: BELSHAW
Magnitude: 65.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Many trees and power lines were blown down across southern Lake County.

Thunderstorm Wind in LAKE, INDIANA
From 04-JUN-11 15:42:00 to 04-JUN-11 15:48:00 (CST-6)
Location: DINWIDDIE
Magnitude: 96.00 EG
Property damage: 300.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The National Weather Service conducted an aerial survey and determined that the damage was spread out across a path approximately two miles wide.  All trees and debris appeared to be blown down in the same direction, to the southeast.
The most intense damage occurred from just east of Interstate 65 and Route 2 southeast toward the Kankakee River and the Lake Porter county line.  A semi truck was blown over near exit 240 and part of the roof of a weigh station was blown off near mile marker 243, both on Interstate 65.  Hundreds of large trees were snapped or uprooted.  Some detached garages, farm outbuildings and grain bins were destroyed or severely damaged.  Homes suffered some loss of shingles.  There were five metal tress electrical towers collapsed near Route 2 and Clay Street.  Although the EF guide would suggest stronger winds may be required to collapse the towers, none of the other nearby observed damage was consistent with wind speeds higher than around 110 mph.

Thunderstorm Wind in JASPER, INDIANA
From 04-JUN-11 16:10:00 to 04-JUN-11 16:12:00 (CST-6)
Location: WHEATFIELD
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Several trees and tree limbs were blown down in and around Wheatfield.