An area of low pressure moved east along Interstate 70 corridor with a warm front extending eastward across southern Illinois and a cold front trailing southwestward along I-44.  Storms developed over central Missouri and tracked east into southern Illinois mainly along I-70 with numerous reports of large hail, with some hail stones up to softball size, as well as a few reports of wind damage.  Some storms continued to produce hail into the early morning hours of April 29th before diminishing.  Overall there were over 100,000 hail damage claims made in Illinois for a total of $665 million in damages.

Hail in MADISON, ILLINOIS
From 28-APR-12 14:42:00 to 28-APR-12 14:49:00 (CST-6)
Location: MADISON
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

There were numerous reports of large hail across Granite City. The largest hail stones were tennis ball size.

Thunderstorm Wind in MADISON, ILLINOIS
From 28-APR-12 14:47:00 to 28-APR-12 14:47:00 (CST-6)
Location: GRANITE CITY
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MADISON, ILLINOIS
From 28-APR-12 14:55:00 to 28-APR-12 14:57:00 (CST-6)
Location: STATE PARK PLACE
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

There were numerous reports of large hail across Collinsville.  The largest hail stones were tennis ball size. Golfball size hail was reported at Cahokia Mounds State Park.

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:01:00 to 28-APR-12 15:05:00 (CST-6)
Location: FRENCH VLG
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

There were numerous reports of large hail across Fairview Heights.  The largest hail stones were tennis ball size reported near the intersection of I-64 and Bunkum Road.  Also, numerous roofs sustained shingle damage and numerous cars sustained dents from the hail stones.

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:05:00 to 28-APR-12 15:15:00 (CST-6)
Location: CARBON
Magnitude: 3.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

There were numerous reports of large hail across O'Fallon.  The largest hail stones were three and a half inches by two inch disc shaped stones. Baseball sized hail was reported at Scott Air Force Base.

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:15:00 to 28-APR-12 15:20:00 (CST-6)
Location: LEBANON
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

There were numerous reports of large hail across Lebanon.  The largest hail stones were baseball size.  Numerous car windows and several windows on homes sustained damage.

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:24:00 to 28-APR-12 15:29:00 (CST-6)
Location: OGLES
Magnitude: 3.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

There were numerous reports of large hail across Belleville and Swansea.  The largest hail stones reported were three inches in diameter. There were numerous reports of damage to vehicles from the hail.

Thunderstorm Wind in ST. CLAIR, ILLINOIS
From 28-APR-12 15:20:00 to 28-APR-12 15:20:00 (CST-6)
Location: SHILOH
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down numerous large tree limbs.

Thunderstorm Wind in ST. CLAIR, ILLINOIS
From 28-APR-12 15:15:00 to 28-APR-12 15:20:00 (CST-6)
Location: GLENVIEW
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm winds blew down several signs along I-64.  Also, a few large trees were snapped off on the southeast side of O'Fallon.

Hail in CLINTON, ILLINOIS
From 28-APR-12 15:28:00 to 28-APR-12 15:47:00 (CST-6)
Location: NEW BADEN
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A swath of large hail was reported in the New Baden area.  There were numerous reports of vehicles with their windows broken both in town and along Interstate 64 between mile markers 27 and 30.  The largest hail stones were baseball size.

Hail in CLINTON, ILLINOIS
From 28-APR-12 15:38:00 to 28-APR-12 15:38:00 (CST-6)
Location: AVISTON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLINTON, ILLINOIS
From 28-APR-12 15:50:00 to 28-APR-12 15:50:00 (CST-6)
Location: GERMANTOWN
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLINTON, ILLINOIS
From 28-APR-12 15:50:00 to 28-APR-12 15:50:00 (CST-6)
Location: BREESE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:28:00 to 28-APR-12 15:28:00 (CST-6)
Location: MASCOUTAH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:45:00 to 28-APR-12 15:50:00 (CST-6)
Location: MASCOUTAH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, ILLINOIS
From 28-APR-12 16:20:00 to 28-APR-12 16:20:00 (CST-6)
Location: OKAWVILLE
Magnitude: 4.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, ILLINOIS
From 28-APR-12 16:37:00 to 28-APR-12 16:37:00 (CST-6)
Location: COVINGTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, ILLINOIS
From 28-APR-12 16:55:00 to 28-APR-12 16:55:00 (CST-6)
Location: VENEDY STATION
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in WASHINGTON, ILLINOIS
From 28-APR-12 17:07:00 to 28-APR-12 17:07:00 (CST-6)
Location: OKAWVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in FAYETTE, ILLINOIS
From 28-APR-12 17:50:00 to 28-APR-12 17:50:00 (CST-6)
Location: ST ELMO
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm winds blew down several power lines and large tree limbs.

Hail in MARION, ILLINOIS
From 28-APR-12 18:00:00 to 28-APR-12 18:00:00 (CST-6)
Location: KINMUNDY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in FAYETTE, ILLINOIS
From 28-APR-12 18:00:00 to 28-APR-12 18:10:00 (CST-6)
Location: FARINA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Enough hail fell that it looked like it had snowed in Farina.  Dense fog briefly developed due to the large amounts of hail.

Hail in CLINTON, ILLINOIS
From 28-APR-12 18:05:00 to 28-APR-12 18:05:00 (CST-6)
Location: DAMIANSVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in MONROE, ILLINOIS
From 28-APR-12 20:01:00 to 28-APR-12 20:01:00 (CST-6)
Location: BURKSVILLE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in MONROE, ILLINOIS
From 28-APR-12 19:45:00 to 28-APR-12 19:45:00 (CST-6)
Location: VALMEYER
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MONROE, ILLINOIS
From 28-APR-12 19:50:00 to 28-APR-12 19:50:00 (CST-6)
Location: FOSTER POND
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm winds destroyed two garages in town and blew the roofs off of a couple of barns.  Also, some homes sustained shingle damage and several trees were blown over.

Hail in MONROE, ILLINOIS
From 28-APR-12 20:20:00 to 28-APR-12 20:20:00 (CST-6)
Location: HECKER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail was covering the ground.

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 20:30:00 to 28-APR-12 20:30:00 (CST-6)
Location: MARISSA
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail was covering the ground on the southside of Marissa.

Hail in MACOUPIN, ILLINOIS
From 28-APR-12 20:55:00 to 28-APR-12 20:55:00 (CST-6)
Location: WOODBURN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLINTON, ILLINOIS
From 29-APR-12 01:15:00 to 29-APR-12 01:15:00 (CST-6)
Location: AVISTON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MONTGOMERY, ILLINOIS
From 28-APR-12 21:25:00 to 28-APR-12 21:25:00 (CST-6)
Location: LITCHFIELD
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MADISON, ILLINOIS
From 29-APR-12 01:30:00 to 29-APR-12 01:30:00 (CST-6)
Location: EDWARDSVILLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, ILLINOIS
From 28-APR-12 16:55:00 to 28-APR-12 16:55:00 (CST-6)
Location: HOYLETON
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in FAYETTE, ILLINOIS
From 28-APR-12 17:55:00 to 28-APR-12 17:55:00 (CST-6)
Location: ST PETER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in ST. CLAIR, ILLINOIS
From 28-APR-12 15:15:00 to 28-APR-12 15:15:00 (CST-6)
Location: (CPS)EAST STL ARPT C
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, ILLINOIS
From 28-APR-12 16:38:00 to 28-APR-12 16:38:00 (CST-6)
Location: NEW MINDEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter