A sign in a field near Winfield, Mo., during a Mississippi River flood in 2008. The area suffered a similarly serious flood in 1993. The frequency of severity of flooding up and down the river have increased due to climate change and river control structures such as levees.

A sign in a field near Winfield, Mo., during a Mississippi River flood in 2008. The area suffered a similarly serious flood in 1993. The frequency of severity of flooding up and down the river have increased due to climate change and river control structures such as levees.