1. Lower Big Sioux River
NOAA predicted major flooding will continue this spring in the lower Big Sioux River in eastern South Dakota. Major flooding, one of four categories considered by the National Weather Service, is defined as extensive inundation of structures and roads. Significant evacuation of people and property to higher elevations occurs with major flooding. Lower Big Sioux River is one of four major watersheds in the Missouri River Basin — along with the Upper Big Sioux River, Rock River, and Little Sioux River.
2. Vermillion River
NOAA forecast major flooding will continue this spring in the Vermillion River area. Part of the Missouri River Basin, this 59.6-mile waterway snakes through Scott County and Dakota County in Minnesota and enters the Mississippi River floodplain south of the town of Hastings.
3. Lewis and Clark Lake River
The Gavins Point Dam, about four miles west of Yankton, South Dakota, increased water releases in March to leave room for Lewis and Clark Lake to accommodate runoff from heavy rainfall and snowmelt upstream.
4. Lower James River
NOAA has forecast major flooding to continue this spring in the Lower James River in eastern South Dakota. The river is part of the Missouri Basin, which NOAA says has higher-than-normal flood risk this year. Among the conditions leading to flooding are above-normal snowpack across the Plains, saturated soil, and deeply frozen soil. Ice jam flooding has already been reported at many locations in the region this winter.
5. Floyd River
The Floyd River in Iowa is another area in the Missouri River Basin where major flooding is expected this spring. Flooding from the Floyd River inundated communities in 1892, 1926, and 1953. The river is a tributary of the Missouri River, flowing 112 miles in northwestern Iowa. It enters the Missouri at Sioux City. The waterway is named after Charles Floyd, a member of the Lewis and Clark Expedition.