... cities such as Fargo, Minnesota have river valleys fed by glaciers and drainage systems far greater than simple rainfall. 'The head waters' of the Red River starts in Canada.
Red River of the North BasinGlacial Lake Agassiz and the Red River Valley (Click on title above to access site of "Minnesota Pollution Control Agency.")
As the glaciers melt down, there is not only increased percipitation from severe and deluging storms there is also river rise from the glaciers. This is met with sea level rise at the drainage basin. In this case, the mouth of the Mississippi River. Regardless the elevation of the city there will be saturation throughout the entire 'traverse' of the water.
The Gulf Coast of the USA is affected by not only the severe storms but also the rising rivers that provide it's valued commerce. Senator Landreau is correct. She has the 'big picture.'