My office ran an analysis using Sentinel 2A satellite imagery to find out just how much of Baton Rouge flooded, and how much of that flooding was outside of floodplains, or in areas designated as protected by levees. The word is that lots of flooding there is due to backwater effects (water not being able to clear out quickly enough from rain), and it's extensive. In our incomplete analysis, we found 30 square miles (78 sq. km) of flooding in the unclouded part of the image. This web map will let you explore.