Explained: Why the Texas floods were so catastrophic

Catastrophic flash floods hit Texas on Friday (July 4) amid Independence Day celebrations. Nearly 104 people have died while hundreds of others are missing as the deluge struck a children’s summer camp and other holiday spots. Search operations are now underway amid predictions for more rain in the coming days.

The floods were unprecedented. A month’s rainfall was received in just a few hours, causing the Guadalupe River to burst its banks. But what was the reason for such torrential rain?

What caused the flash floods?

The National Weather Service (NWS) has termed flash flooding as a rapid and extreme flow of high water into a normally dry area, which was witnessed on July 4. It mainly occurs when the water level of a stream rises rapidly above the preset flood levels. In the case of the Texas floods, the area was in the middle of a drought, which worsened the situation, reported Associated Press.

Hatim Sharif, a hydrologist at the University of Texas at San Antonio, noted that Texas’s Hill Country sits in an area known as “Flash Flood Alley”. The ascent of warm Gulf air along the Balcones Escarpment, a formidable arc of steep hills and cliffs southwest of Dallas, leads to rapid cooling and intense downpours. These heavy rains quickly wash away the shallow soil, exposing the bedrock beneath. “Water will rise very, very quickly, within minutes or a few hours,” Sharif told AFP.

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This was proved in the early hours of July 4. Around 3:00 am, a gauge near Camp Mystic in Hunt showed the Guadalupe River rising nearly a foot (30 centimetres) every five minutes; by 4:30 am, the river had surged more than 20 feet, National Weather Service data show. That's enough water to sweep away people, vehicles and buildings .

An urgent NWS warning went out shortly after 1 am, but most campers were asleep; phones are banned, coverage is patchy, and darkness makes escape routes hard to judge.

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Sharif urges the use of hydrologic forecasts that convert rainfall into likely river levels. “Rainfall needs to be translated into runoff,” he said. “If you have 10 inches, what will happen?”

Summer camps have long been drawn to the region for its natural beauty. But with increasing risks, Sharif warns that treating these sites as safe or permanent is unwise.

Is climate change to blame?

Climate change has come up once again in conversations after the floods. According to a new analysis by ClimaMeter, the extreme meteorological conditions preceding the floods, delivering more than double the typical monthly rainfall in just one day, suggest a cause beyond natural climate fluctuations.

“Climate change is already affecting us, so we need to adapt,” said Mireia Ginesta, a climate scientist at the University of Oxford, who co-authored the research, which is funded by the European Union and the French National Centre for Scientific Research (CNRS). “We also need to cut our emissions, and make sure that proper funding is provided to the forecast services and research in general on climate change.”

The call comes as the National Weather Service, like other agencies, has experienced deep staffing cuts under President Donald Trump’s administration.

Experts stress, however, that NWS forecasters performed admirably under the circumstances. The real failure, wrote climate scientist Daniel Swain on Bluesky, “was not a bad weather prediction, it was one of ’last mile’ forecast/warning dissemination.”

Was there a warning system in place?

According to USA TODAY, the  NWS issued flash flood alerts just after 1 am and 4 am , but since most people near the river were asleep, they missed it altogether.

A “flood watch” was issued July 3 with the weather agency stating that there was a “slight risk” of flash flooding. But there was nothing indicating catastrophic floods like what took place in the early morning hours of July 4, the report said.

For years, commissioners in Kerr County, where the camps lie, considered flood sirens and digital alerts to replace the informal practice of summer camp staff getting on the radio and warning fellow camps.

Minutes from a 2016 meeting show officials labelling even a feasibility study “a little extravagant,” suggesting sirens would mainly help tourists, and vouching for the word-of-mouth system.

“The thought of our beautiful Kerr County having these damn sirens going off in the middle of night, I’m going to have to start drinking again to put up with y’all,” Commissioner HA Buster Baldwin said in a transcript.

The debate rolled on . Residents during meetings in 2021 expressed strident opposition toward relying on federal funds tied to the Biden administration.

After the disaster, San Antonio mother Nicole Wilson, who almost sent her daughters to Camp Mystic, launched a petition on Change.org urging Governor Greg Abbott to approve a modern warning network. “Five minutes of that siren going off could have saved every single one of those children,” she told AFP.

With inputs from agencies