SOUTH DAKOTA FLOW REPORT
Last Updated: December 22, 2025
Rivers and streams across South Dakota are exhibiting a variety of streamflow conditions ranging from remarkably high flows to those below average, capturing the interest of water enthusiasts and indicating potential environmental concerns. Notably, the Whetstone River near Big Stone City is experiencing an extraordinary high with a current streamflow of 29,300 cubic feet per second (cfs), a massive increase of 76,401.31 cfs from the previous 24 hours, which suggests an alarming situation that could potentially lead to flooding; the flow is 2,426.97% of the normal rate for this time of year. Similarly, the Belle Fourche River near Elm Springs is significantly above normal at 727.05% of its average flow, currently at 17,900 cfs. These abnormal conditions could affect surrounding areas, including communities and popular whitewater trails, and warrant monitoring for flood risks.
Conversely, the Big Sioux River, which is a focal point for river recreation near cities like Sioux Falls, is flowing closer to normal levels, with the flow at North Cliff Avenue at Sioux Falls recorded at 471 cfs, or 45.16% of normal, with a slight decrease over the last 24 hours. However, the James River near Yankton and Scotland is showing less than average flows at -8.43% and -13.65% of normal, respectively, which could indicate flow droughts within these regions. These variations in streamflow underscore the importance of staying updated on current river conditions for safety and the health of the South Dakota aquatic ecosystems.
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.
Winter Storm Warnings
December 22 2025
Residents of the Hermosa and Southern Foothills in South Dakota should brace for strong winds as the National Weather Service in Rapid City has issued a Wind Advisory effective until 3 PM MST today. Westerly winds are expected to reach speeds of 20 to 30 mph with gusts up to 50 mph. These conditions pose a risk for drivers, particularly those in lightweight or high-profile vehicles, and could lead to loss of vehicle control. The advisory also warns of possible blowing dust, reduced visibility, and flying debris. It is advised to secure outdoor objects and exercise caution while traveling in the affected areas.