COLUMBUS — Polk County authorities have closed the highway between Osceola and Shelby after overnight rainfall measurements indicate that 2 to nearly 4 inches of rain pounded the area. According to Polk County Sheriff Dwaine Ladwig the highway had to be closed due to water overtaking the highway. The National Weather Service issued a Flood Warning for the area until Tuesday morning. At 9:37 a.m., emergency management reported extensive flooding. Part of Highway 81/92 is impassable and is closed from three miles east of Shelby to 3 miles west of Osceola. Some locations that are experiencing flooding include Stromsburg, Osceola, Shelby, Polk and Bradshaw. The Flood Warning is in effect for all of Polk County and northwestern York County.