On August 4 at 9:25 am EST a major thunderstorm producing large hail and winds in excess of 60 mph (97 km/h) advanced at the leading edge of a cold front moving across the American Midwest, causing a flash flood that struck Louisville and portions of the surrounding Kentuckiana region. The National Weather Service estimated that between three and six inches of rain fell(14–24 cm) across the city in less than one hour, breaking all previous one-hour rainfall records in the area. Most of the downtown area was underwater, with the deluge reaching 4 feet (1.2 m) deep in places. The flood was the third major disaster to strike the region in less than one year.