(CHICAGO) Record rainfall Saturday triggered a flash flood warning as heavy rains and thunderstorms moved through the Chicago area.

The flash flood warning affected the Chicago area, as well as Cook, DuPage, Kane, Kendall, Lake, McHenry, Boone, DeKalb, La Salle, Ogle and Winnebago counties, according to the National Weather Service.

Rainfall flooded the MacDonald’s Hamburger University Campus in Oak Brook, which caused cancellation of Sunday morning;’s 5k Run/Walk sponosred by the Freedom Gold Association. The even will be resheduled.

The showers Saturday poured 4.19 inches of rain on O’Hare International Airport, marking the wettest October day in the city in recorded history, forecasters said.

The rainfall caused the Chicago River to overflow its downtown banks and submerge most of the popular Chicago Riverwalk. Chicago Police taped off several entryways between Franklin Street all the way east to Lake Michigan as the city’s iconically greenish river spilled over most of the scenic walkway.

The showers and thunderstorms were expected to continue pounding the area until Sunday morning, with a 30 percent chance of showers before 8 a.m., the weather service said. Sunday as expected to be cloudy and the temperature was forecast to drop to around 52 degrees by noon.

The rainfall was expected to stop for the rest of the week, the weather service said.