In August 2017, Hurricane Harvey dumped more than four feet of rain on Houston, Texas, in a matter of days, sending unprecedented floods through one of the largest cities in the U.S.

In the deluge’s aftermath, climate scientists noted that storms like Harvey are rare—but cautioned that unusually warm waters, made likelier by human activity, may have supercharged the hurricane’s extreme rainfall. Now, two separate teams of scientists have found humans’ fingerprints all over the storm.

One research team’s results, accepted for publication in Geophysical Research Letters (GRL), found that in comparison to a typical 1950s hurricane, climate change likely increased Harvey’s seven-day rainfall by at least 19 percent. A separate study, published today in Environmental Research