Flash Flood — Carroll, Illinois

2010-07-24 to 2010-07-25 · near Lanark, Carroll, Illinois

Event narrative

After about a foot of rain in 2 days, creek and small river basins rose rapidly Saturday morning. Numerous rural roads throughout the county suffered from washouts and excessive erosion. Near Argo Fay, Johnson Creek overflowed its banks and closed Big Cut Road.

In Mount Carroll, flooding of the Waukarusa River forced evacuations of about 80 homes, mainly on or near Mill Street. The local fire chief estimated that 80% of Mount Carroll residences had water in their basements.

The Plum River overflowed its banks between Lake Carroll and Savanna, causing extensive and severe damage. Just west of Lake Carroll, a farm house on Polsgrove Road flooded. The resident of the home described the event, saying that around 5 am there was no sign of flooding nearby, and by 7 am water was in the house.

As the flood waters approached Savanna, the Plum River either overflowed or breached (it is unclear which) a high bank along Scenic Bluff Road, flowing then through the railroad yard to the Mississippi River. Local residents describe water rising about 4 feet in literally a few minutes. In Savanna, an estimated 625 people were evacuated, mainly from the eastern and southern portions of town. Due to the rapidly rising water, first responders in Savanna rescued more than 60 people from their homes. At least 12 homes suffered water up to the first floor and a Swiss Colony factory had several feet of water throughout its facility. Emergency management estimated 10 homes completely destroyed and 75 seriously damaged in Savanna alone. The raging flood waters washed away more than 30 yards of embankment supporting an overpass on the Highway 84 viaduct, washing away two rows of pylons that were supporting the bridge and closing the primary access route south of Savanna indefinitely. Numerous rail cars in the train yard were overturned, some of them washed up against bridges. Both DM&E and Burlington Northern suffered damage to their rail lines.

Wider weather episode

Still supported by a nearby stationary front, a second round of thunderstorms dropped another 3-5 inches of rain across northwest Illinois during the overnight hours of July 23rd into the early morning of July 24th. This additional heavy rain exacerbated the ongoing flooding from the night before and caused even more extensive and severe damage. Yellow Creek and the Pecatonica River (Stephenson County), the Apple and Galena Rivers (Jo Daviess County), and the Plum River were most notably affected.

View location on OpenStreetMap → (42.1942, -89.8915)

Source: NOAA Storm Events Database, event_id 253430. Narrative written by the NWS forecast office that issued the report.