The Mississippi River that borders Missouri has plenty of dangers all its own without adding sharks to the equation. You'd think you'd be safe from that worry, but sharks swimming up the Mississippi River as far north as Missouri happens more often than you think.
If you think forecasting the weather is hard, you should see all the factors that go into predicting what rivers will do. There is reason for concern though as it appears there's a growing chance that the Mississippi River will exceed flood stages this Spring along its banks in Missouri and Illinois.