People living in the American Southwest have seen their share of drought. But the West’s recent water woes may pale in comparison to what’s coming later in the century, researchers say. The Southwest may very well face a decades-long megadrought before the 21st century is out.

A team climate scientists led by Toby Ault, an atmospheric researcher at Cornell University, has just calculated the risk of a Southwestern megadrought occurring by 2100. By “megadrought” they mean an extreme, bone-dry period that can last for more than 35 years.