A study last week predicts that massive, often-devastating “hundred-year storms” may occur three times as often and be 20% more severe in the U.S. due to climate change. The researchers, in a paper published in the American Geophysical Union journal Earth’s Future, found that if greenhouse gas emissions continue to increase at a rapid rate, the continental U.S. would likely see such mega-storms every 33 years.

The occurrence of historic rainfall events, like the ones that caused Hurricane Harvey in 2017 and California’s Great Flood of 1862, are likely to increase faster than lower-magnitude events, which already happen about every decade, according to UCLA climate scientist Daniel Swain.