The science behind Texas' catastrophic floods

The science behind Texas’ catastrophic floods
At least 95 people died in the flash floods. The disaster has the fingerprints of climate change all over it.

Matt Simon
Senior Staff Writer


(Grist) Rescue crews are scrambling to find survivors of catastrophic flooding that tore through Central Texas on the Fourth of July. It’s already one of the deadliest flood events in modern American history, leaving at least 95 people dead, 27 of whom were girls and counselors at a Christian summer camp in Kerr County, which was inundated when the nearby Guadalupe River surged 26 feet in just 45 minutes.

“It’s the worst-case scenario for a very extreme, very sudden, literal wall of water,” said Daniel Swain, a climate scientist at the University of California, Los Angeles, during a livestream Monday morning. “I don’t think that’s an exaggeration in this case, based on the eyewitness accounts and the science involved.”

It will take some time for scientists to do proper “attribution” studies here, to say for instance how much extra rain they can blame on climate change. But generally speaking, this disaster has climate change’s marks all over it — a perfect storm of conspiring phenomena, both in the atmosphere and on the ground. “To people who are still skeptical that the climate crisis is real, there’s such a clear signal and fingerprint of climate change in this type of event,” said Jennifer Francis, senior scientist at the Woodwell Climate Research Center.

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Even when a hurricane isn’t brewing, the gulf is sending more moisture into the atmosphere — think about how your bathroom mirror fogs up when you draw a hot bath. This pushes wet, unstable air higher and higher into the atmosphere, condensing into clouds. As these systems release heat, they grow even more unstable, creating a towering thundercloud that can drop extreme amounts of rainfall. Indeed, preceding the floods, the amount of moisture above Texas was at or above the all-time record for July, according to Swain. “That is fairly extraordinary, in the sense that this is a place that experiences very moist air this time of year,” Swain said. ......................(more)

https://grist.org/climate/the-science-behind-texas-catastrophic-floods/