See the invisible force driving destructive floods across the U.S.

Some of the most extreme weather in the United States this summer have been driven by an invisible force pooling in the skies above: water vapor.

Although recent destructive floods in Hawaii, Indiana, Kentucky, Missouri, New York, Texas, West Virginia and many other states may seem geographically disconnected, they share a link to something happening thousands of miles away, in a remote stretch of the tropical Pacific Ocean.