A strong storm system was approaching the region. Numerous storms developed ahead of the system during the late morning and afternoon hours on May 23rd.  There were numerous reports of damaging winds and large hail.

Hail in MARION, ILLINOIS
From 23-MAY-11 12:13:00 to 23-MAY-11 12:13:00 (CST-6)
Location: SANDOVAL
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MARION, ILLINOIS
From 23-MAY-11 12:30:00 to 23-MAY-11 12:30:00 (CST-6)
Location: SALEM
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in MARION, ILLINOIS
From 23-MAY-11 12:15:00 to 23-MAY-11 12:15:00 (CST-6)
Location: SANDOVAL
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down several large tree limbs.

Hail in MARION, ILLINOIS
From 23-MAY-11 13:04:00 to 23-MAY-11 13:04:00 (CST-6)
Location: CENTRALIA
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in FAYETTE, ILLINOIS
From 23-MAY-11 12:40:00 to 23-MAY-11 12:40:00 (CST-6)
Location: BINGHAM
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Thunderstorm winds blew down a large tree.  The tree fell onto the roof of a church causing minor damage to one corner of the roof.  The tree also knocked down a power line.

Thunderstorm Wind in ST. CLAIR, ILLINOIS
From 23-MAY-11 11:50:00 to 23-MAY-11 11:50:00 (CST-6)
Location: SWANSEA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Thunderstorm winds blew down a couple of trees.  One tree landed on West Main Street and the other on Summit Avenue.

Thunderstorm Wind in MACOUPIN, ILLINOIS
From 23-MAY-11 12:10:00 to 23-MAY-11 12:10:00 (CST-6)
Location: STAUNTON
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Thunderstorm winds blew over a semi on the north bound lanes of I-55 just south of the Staunton exit.  The driver lost control when the truck was hit by the winds and ended up in a ditch about 50 feet from the road.  The driver sustained minor injuries.

Thunderstorm Wind in MADISON, ILLINOIS
From 23-MAY-11 11:48:00 to 23-MAY-11 11:48:00 (CST-6)
Location: MADISON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds caused minor damage to a chimney.  Also, part of the roof of a building was blown off near the intersection of 23rd Street and Washington Avenue.  Several large trees were blown down around town.

Thunderstorm Wind in MADISON, ILLINOIS
From 23-MAY-11 11:55:00 to 23-MAY-11 12:02:00 (CST-6)
Location: GLEN CARBON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down a twelve inch diameter tree on Clay Street in Troy.  Also, numerous large tree limbs were blown down in Glen Carbon and Edwardsville.

Thunderstorm Wind in MADISON, ILLINOIS
From 23-MAY-11 11:42:00 to 23-MAY-11 11:48:00 (CST-6)
Location: WOOD RIVER
Magnitude: 73.00 MG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: AWOS

The 86 mph wind gust caused some damage to the St. Louis Regional Airport's administration building.  The winds partially caved in the building's 80 foot long, 25 foot high door.  It will cost about $15,000 to repair the door, if that is possible, and between $100,000 and $125,000 to replace, if necessary.  In Wood River, numerous trees, power poles and power lines were blown down.  A few of the trees landed on the roofs of houses.  Some of the houses sustained minor to moderate roof damage because of this.  Also, a dugout on the softball field at East Alton-Wood River High School had its roof blown off.  No injuries were reported.