Significant flooding developed after two thunderstorm complexes crossed southern Illinois, bringing 72-hour rainfall totals to nearly one foot in isolated locations. A large complex of thunderstorms moved southeast across southern Illinois during the evening hours of the 29th. These storms occurred near a surface cold front which sagged southward across southern Illinois during the evening. During the overnight hours through the early morning of the 30th, an even larger complex of thunderstorms dumped widespread very heavy rain. This complex occurred along the same front, which moved back north as a warm front. These storms caused considerable flash flooding. They also accelerated rises in area rivers, which were already above flood stage in some cases. The rainfall total for the three-day period from April 28 to April 30 was 11.27 inches at a television station in Carterville (Williamson County). A co-operative observer at Carbondale measured 10.37 inches over the three-day period. In West Frankfort (Franklin County), a Cocorahs observer measured 10.16 inches. North of the Ohio River counties, there were numerous reports of rainfall in the 5 to 10 inch range, including 9.75 inches at Ridgway (Gallatin County), 9.34 inches at Marion, 8.75 inches at West Frankfort (Franklin County), and 8.75 inches at Du Quoin (Perry County). Lesser amounts were reported in far southern counties bordering the Ohio River.

Flash Flood in FRANKLIN, ILLINOIS
From 30-APR-17 05:23:00 to 30-APR-17 16:00:00 (CST-6)
Location: ORIENT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Flash flooding was observed throughout West Frankfort and along Highway 37 north and south of town. Several other roads were closed around the county.

Flash Flood in JEFFERSON, ILLINOIS
From 30-APR-17 08:00:00 to 30-APR-17 16:00:00 (CST-6)
Location: WALTONVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Most creeks were full, and some creeks were overflowing. Low areas were completely flooded. Township roads in low-lying areas were impassable. A trained spotter reported 4.3 inches of rain had fallen overnight.

Flood in WHITE, ILLINOIS
From 29-APR-17 11:00:00 to 30-APR-17 23:59:00 (CST-6)
Location: CARMI
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Little Wabash River rose above flood stage. Through the end of April, the flooding was mostly minor to moderate. However, the river continued rising beyond the end of the month.

Flood in FRANKLIN, ILLINOIS
From 29-APR-17 23:00:00 to 30-APR-17 23:59:00 (CST-6)
Location: PLUMFIELD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Big Muddy River rose above flood stage. Through the end of April, the flooding was mostly minor. The river continued rising beyond the end of the month.

Flood in WAYNE, ILLINOIS
From 30-APR-17 06:45:00 to 30-APR-17 23:59:00 (CST-6)
Location: WAYNE CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

Major flooding occurred on the Skillet Fork River. The river rose rapidly above flood stage on the 30th, climbing about 20 feet in 24 hours. The river continued rising beyond the end of the month.

Flash Flood in WHITE, ILLINOIS
From 30-APR-17 10:40:00 to 30-APR-17 16:00:00 (CST-6)
Location: CROSSVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A creek in Crossville quickly overtopped its banks.

Flash Flood in JACKSON, ILLINOIS
From 30-APR-17 05:30:00 to 30-APR-17 16:00:00 (CST-6)
Location: GRAND TOWER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Many roads were closed around the county, mainly smaller back roads.

Flash Flood in HAMILTON, ILLINOIS
From 30-APR-17 05:05:00 to 30-APR-17 16:00:00 (CST-6)
Location: FEAKEYVILLE
Flood cause: Heavy Rain
Property damage: 6.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The community of Broughton was isolated by high water. Highway 142 was closed from south of Dale to the Saline County line. Numerous secondary roads were covered by water. A couple of homes received minor flood damage in the Mcleansboro area.

Flood in MASSAC, ILLINOIS
From 30-APR-17 00:00:00 to 30-APR-17 23:59:00 (CST-6)
Location: BROOKPORT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

Minor flooding occurred along the Ohio River as the month ended. Low-lying woods and fields near the river were under water. Portions of Fort Massac State Park were flooded, prompting the closure of the riverfront area of the park.

Flash Flood in SALINE, ILLINOIS
From 30-APR-17 05:05:00 to 30-APR-17 16:00:00 (CST-6)
Location: FRANCIS
Flood cause: Heavy Rain
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Water levels around Harrisburg continued to rise even after the rain ceased. Many businesses in Harrisburg were threatened, and a fast-food restaurant and a large retail store closed due to the flooding. Dozens of volunteers sandbagged businesses and homes. Travel was hampered by the flooding. Highway 142 was closed due to high water north of Eldorado to the Hamilton County line. Numerous city streets in Harrisburg, as well as county roads outside the city, were under varying amounts of water.

Flash Flood in WILLIAMSON, ILLINOIS
From 30-APR-17 05:28:00 to 30-APR-17 16:00:00 (CST-6)
Location: JOHNSTON CITY
Flood cause: Heavy Rain
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous roads were closed, including Highway 37 south of Johnston City. Some homes in Marion were flooded. The American Red Cross opened a shelter in Marion, where 22 evacuees spent the night.

Flash Flood in PERRY, ILLINOIS
From 30-APR-17 05:35:00 to 30-APR-17 16:00:00 (CST-6)
Location: OLD DUQUOIN
Flood cause: Heavy Rain
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A well-traveled county road was closed from east of Du Quoin to the Franklin County line. In addition, a portion of Route 3 was closed just east of U.S. Highway 51, a few miles north of Du Quoin. Many smaller back roads were closed. A rural road near Pinckneyville was washed out. In the city of Pinckneyville, a street was closed due to several feet of water.

Flood in JACKSON, ILLINOIS
From 29-APR-17 07:00:00 to 30-APR-17 23:59:00 (CST-6)
Location: MURPHYSBORO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

Through the end of April, flooding along the Big Muddy River was mostly minor to moderate. However, this was the beginning of a major flood along the Big Muddy River. The river continued rising beyond the end of the month.

Flood in ALEXANDER, ILLINOIS
From 29-APR-17 10:30:00 to 30-APR-17 23:59:00 (CST-6)
Location: THEBES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Mississippi River rose above flood stage at the end of the month. Through the end of April, the flooding was mostly minor to moderate. However, this was the start of major flooding along the river. The river continued rising past the end of the month.