When the National Oceanic and Atmospheric Administration warned in March of major flooding in the Midwest, it noted that major rains could combine with heavy snow melts to put more than 200 million people at risk.

That’s exactly what has happened.

Heavy rainstorms have stalled over the region for more than a month, filling the Mississippi, Missouri, and Arkansas rivers to near-historic proportions. In St. Louis, waters reached 42 feet as of Tuesday, and the waters rose to 31 feet in Jefferson City, Missouri, the state capital, which was also hit recently by a tornado. Flood watches are in effect along virtually the entire lengths of the rivers.