As the Upper Midwest received yet another round of rainfall over Memorial Day weekend, the floods of 2019 on the major river systems were extended into mid-June at least. The floods have been ongoing since last fall and winter, when the region received twice the usual amount of snowfall. That was just the beginning. The 12-month period from April 2018 to May has turned out to be the wettest year since record-keeping began in 1895, according to the National Oceanic and Atmospheric Administration. On top of that came an unusual Bomb Cyclone in mid-March that sluiced heavy rainwaters off frozen ground into already-swollen rivers. That prompted some of the worst flooding so far.