Flood in Richardson County, Nebraska

During the early morning hours of June 5, 2026, thunderstorms producing heavy rainfall triggered flash flooding across southern Richardson County. Consecutive rounds of thunderstorms generated intense rainfall rates of 1.50 to 3.00 inches per hour, driving estimated total rainfall to between 4.00 and 6.00 inches. As a result, the Big Nemaha River gauge at Falls City (FLLN1) rose above flood stage at 2:45 AM CST on June 5th. The gauge crested at 31.09 ft, consistent with moderate flooding, at 11:28 AM CST on June 5th. The gauge fell below flood stage at 2:45 AM CST on June 6th.

During the afternoon and evening of June 5, 2026, a stalled frontal boundary draped from southeast Nebraska into southwest Iowa served as the focal point for severe thunderstorm development. As an approaching shortwave disturbance provided the necessary forcing for ascent, thunderstorms initiated along the boundary. The surrounding environment was characterized by strong deep-layer shear and robust instability, capable of supporting all severe hazards. Additionally, high atmospheric moisture content situated over already saturated soils generated efficient rainfall processes, elevating flash flooding concerns. These storms initially erupted as brief, discrete cells before rapidly undergoing upscale growth into a larger convective complex.

During the initial discrete phase, the dominant hazard was large hail, with hailstones measured up to 2.00 inches in diameter. The rotating updrafts also produced a couple of funnel clouds, including a photographed rope funnel near Hallam and another near Swanton, though they remained aloft, and no tornadoes were confirmed. As the storms merged into a larger complex, the primary threat shifted to damaging straight-line winds. Multiple stations measured severe wind gusts peaking at 68 mph, which resulted in localized thunderstorm wind damage across the region before the system eventually weakened.