Record-breaking rainfall from the tropical storm Imelda is soaking southeastern Texas. Some areas have been swamped with 20 to 42 inches (51 to 107 centimeters) of rain over just three days, causing catastrophic flooding that is among the worst in U.S. history.

Imelda, the first named storm to strike this part of Texas since 2017’s devastating Hurricane Harvey, is currently the fifth-wettest tropical storm to drench the contiguous U.S., The Weather Channel tweeted today (Sept. 19).

Storms that drop this much rain are estimated to appear once in a millennium, according to precipitation models created by the National Oceanic and Atmospheric Administration (NOAA).

But the last 1,000-year-rainfall to inundate Texas was Hurricane Harvey — which slammed the state just two years ago.