EF4 tornado in Gallatin County, Illinois

The tornado crossed into Gallatin County from Saline County in the vicinity of Illinois Highway 142. The tornado moved east-northeast through very sparsely populated farm country before striking Ridgway directly. In Ridgway, the tornado damaged about 140 homes and businesses, causing one critical injury and about a dozen relatively minor injuries. Numerous cars were tossed around, mainly on the east side of Ridgway. A large historic church was completely destroyed. Hundreds of large trees were snapped or uprooted, along with many power lines down. A half dozen grain bins were destroyed. The tornado lifted about 4 miles east-northeast of Ridgway. The average path width was 275 yards. Peak winds were estimated near 180 mph.

A squall line with embedded sustained supercells crossed southern Illinois. The embedded supercells raced east-northeast at 60 to 70 mph, while the line moved southeast at a slower rate. The storms strengthened as they encountered richer low-level moisture, with surface dew points around 60 degrees spreading rapidly north-northeastward up the Mississippi Valley. Intense low to mid-level wind fields maintained the intensity of tornadic storms despite weak instability due to lack of solar heating. A south-southwesterly low level jet from 60 to 70 knots veered to west-southwest around 75 knots at 500 mb.