National Weather Service United States Department of Commerce
The National Weather Service completed a service assessment for flooding along the Missouri and Souris Rivers that occurred from May through August 2011. The final report of this assessment may be read at:
 
 
Service assessments are internal reviews of the National Weather Service’s performance during certain Hydrometeorological, oceanographic, and geological events. They identify best practices and areas for product and service improvements in the form of findings and recommendations.
 
Additional information regarding this and other floods across South Dakota from 1881 to 2019 can be found here, courtesy of the U.S. Corps of Engineers (alternatively here, via the South Dakota State Historical Society).