U.S. Megadrought Is Worst for Over 1,000 Years: How Long Could It Last?

Droughts are periods characterized by abnormally dry conditions. But what are megadroughts, and how bad is the one currently affecting parts of the United States?

While there are no clear definitions of what a megadrought is, in general these events are defined as droughts that last for multiple decades, i.e. two or more, according to Ashok Mishra, a professor in the Glenn Department of Civil Engineering at Clemson University.

"Although there may be a few wet spells, most periods remained dry," he told Newsweek.