SOUTH DAKOTA FLOW REPORT
Last Updated: December 4, 2025
South Dakota's river systems are experiencing significant and varied streamflow conditions as of the latest data, with some areas facing potential flooding while others remain within normal ranges. Notably, the Whetstone River near Big Stone City is recording an extraordinary streamflow of 29,300 cubic feet per second (cfs), a dramatic 24-hour increase of 76,401.31 cfs, indicating a potential flooding situation as this is 2,426.97% above the norm, with a current gage height of 22.95 feet. Conversely, the Redwater River above Belle Fourche is at a mere 0.47% of its typical flow, signaling a flow drought with a current streamflow of 183 cfs and a minor decrease of 3.68 cfs over the past 24 hours. These anomalies in streamflow highlight the contrasting hydrological stresses within the state.
In the vicinity of Belle Fourche, water enthusiasts should be aware of the Belle Fourche River near Elm Springs, which is experiencing a substantial flow of 17,900 cfs, 727.05% above the average, potentially affecting nearby whitewater trails. Meanwhile, the Cheyenne River basin shows varied conditions, with the Cheyenne River at Redshirt flowing at 126.58% of its average rate with a current streamflow of 311 cfs and a gage height of 9.82 feet. Cities along the James River need to be attentive as streamflows range from 409 cfs near Stratford to 752 cfs near Yankton, with the river's health fluctuating between near-normal to minor low-flow conditions. Recreational users of the popular Big Sioux River should note flows are currently within safer levels, such as near Brookings with a streamflow of 388 cfs and near Sioux Falls at 471 cfs, albeit these are 20.5% and 45.16% of the average flows, respectively. These conditions across South Dakota's rivers and streams underscore the need for residents and visitors to stay informed and exercise caution near water bodies during these dynamic hydrological changes.
South Dakota has a humid continental climate with four distinct seasons. The Missouri River, which forms the eastern border of the state, is the largest and most significant surface flow. It is subject to extreme flooding during spring and summer due to snowmelt and heavy rainfall. Other major rivers include the Cheyenne, James, and Big Sioux. The state has several reservoirs and dams, including the Oahe, Fort Randall, and Big Bend dams, which provide flood control, irrigation, and hydroelectric power. South Dakota's hydrology is influenced by its topography, soil type, and vegetation cover, which affect the amount and rate of water infiltration and runoff. The state's snowpack and precipitation patterns are important factors in determining water availability and storage.