What killed Stacy Ruffin?

Updated 1014 GMT (1814 HKT) August 11, 2017

John D. Sutter is a columnist for CNN who focuses on climate change and social justice. Follow him on Snapchat, Twitter and Facebook.

Arcola, Louisiana (CNN)Rain pounded on the roof of the mobile home as the phone rang. The call was about Mark, Carolyn Ruffin's oldest son. He'd been hospitalized in a nearby town. The mother of four, who normally has an unflappable air about her, knew she had to rush to her boy -- no matter that a storm was brewing, the likes of which her corner of Louisiana never had seen.

This was August 12, 2016. In the next week, about 7 trillion gallons of water would fall on Louisiana, more than during Hurricane Katrina, according to meteorologist Ryan Maue. The nameless storm would shatter records, flood homes and kill 13 people.
That morning, though, Carolyn's thoughts weren't focused on the weather. They were with her son. So, at about 7 a.m., she hopped in the front seat of a friend's pickup truck.
Two people would join her. One was Alfred Waxter, the truck's owner, a close family friend visiting from Mississippi. The other was Carolyn's daughter Stacy.
At 44, Stacy Ruffin was the youngest of Carolyn's four children. Family members speak of the two as inseparable, and they mean it literally. Stacy lived with her mother in the mobile home, raising a daughter and son of her own there. She managed the deli counter at the Walmart in a neighboring town. Otherwise, she was at her mother's side, helping run errands, pay bills, check on neighbors. Stacy's eight aunties and uncles -- and their children -- all were part of her flock.
She was the family caretaker. The responsible one. The one you turned to.
So it's no surprise she went with her mother to check on her brother.
And it's no surprise that, one year after the storm, no one has filled her void.

'Natural' disaster

Hundreds of miles away, the email landed in the scientists' inboxes.
It was four days later, August 16. The request: Would Karin van der Wiel, Sarah Kapnick and Gabriel Vecchi -- three researchers from the US National Oceanic and Atmospheric Administration's lab in Princeton, New Jersey -- help assess the extreme rainfall in Louisiana?
The floods in Louisiana had caught the attention of the World Weather Attribution team coordinated by Climate Central, a nonprofit that focuses on climate change science and journalism. And they wanted help.