Texas Hill Nation is thought for its landscapes, the place shallow rivers wind amongst hills and thru rugged valleys. That geography additionally makes it one of many deadliest locations within the U.S. for flash flooding.
Within the early hours of July 4, 2025, a flash flood swept by an space of Hill Nation dotted with summer season camps and small cities about 70 miles west of San Antonio. At the very least 43 individuals died, and about two dozen women from one camp had been nonetheless unaccounted for the next day, officers mentioned. Greater than 200 individuals needed to be rescued, and extra rain was forecast by the weekend.
The flooding started with a heavy downpour that despatched water sheeting off the hillsides and into creeks. The creeks poured into the Guadalupe River.
A river gauge at Hunt, Texas, close to the camp, confirmed how rapidly the water rose: Round 3 a.m. on July 4, the river was rising about 1 foot each 5 minutes there, Nationwide Climate Service knowledge exhibits. By 4:30 a.m., it had risen greater than 20 toes.
Flood skilled Hatim Sharif, a hydrologist and civil engineer on the College of Texas at San Antonio, explains what makes this a part of the nation, often known as Flash Flood Alley, so harmful.
What makes Hill Nation so vulnerable to flooding?
Texas as an entire leads the nation in flood deaths, and by a large margin. A colleague and I analyzed knowledge from 1959 to 2019 and located 1,069 individuals had died in flooding in Texas over these six many years. The following highest whole was in Louisiana, with 693.
Lots of these flood deaths have been in Hill County, an space often known as Flash Flood Alley. It’s a crescent of land that curves from close to Dallas right down to San Antonio after which westward.
The hills are steep, and the water strikes rapidly when it floods. This can be a semi-arid space with soils that don’t absorb a lot water, so the water sheets off rapidly and the shallow creeks can rise quick.
When these creeks converge on a river, they’ll create a surge of water that wipes out properties and washes away vehicles and, sadly, anybody in its path.
Hill Nation has seen some devastating flash floods. In 1987, heavy rain in western Kerr County rapidly flooded the Guadalupe River, triggering a flash flood just like the one in 2025. Ten youngsters being evacuated from a camp died within the dashing water.
San Antonio, on the jap fringe of Hill Nation, was hit with a flash flood on June 12, 2025, that killed 13 individuals whose vehicles had been swept away once they drove into excessive water from a flooding creek close to an interstate ramp within the early morning.
Why does the area get such robust downpours?
One motive Hill Nation will get highly effective downpours is the Balcones Escarpment.
The escarpment is a line of cliffs and steep hills created by a geologic fault. When heat air from the Gulf rushes up the escarpment, it condenses and can dump loads of moisture. That water flows down the hills rapidly, from many various instructions, filling streams and rivers under.
As temperature rise, the hotter ambiance can maintain extra moisture, rising the downpour and flood threat.
The identical impact can contribute to flash flooding in San Antonio, the place the big quantity of paved land and lack of up to date drainage to manage runoff provides to the danger.
What will be finished to enhance flash flood security?
First, it’s necessary for individuals to grasp why flash flooding occurs and simply how briskly the water can rise and movement. In lots of arid areas, dry or shallow creeks can rapidly refill with fast-moving water and develop into lethal. So individuals ought to pay attention to the dangers and take note of the climate.
Bettering flood forecasting, with extra detailed fashions of the physics and water velocity at completely different places, may assist.
Probabilistic forecasting, for instance, can present a spread of rainfall eventualities, enabling authorities to organize for worst-case eventualities. A scientific framework linking rainfall forecasts to the native impacts, akin to streamflow, flood depth and water velocity, may additionally assist decision-makers implement well timed evacuations or highway closures.
Training is especially important for drivers. One to 2 toes of shifting water can wash away a automobile. Individuals might imagine their vans and SUVs can undergo something, however fast-moving water can flip a truck and carry it away.
Officers may do extra to barricade roads when the flood threat is excessive to forestall individuals from driving into hurt’s approach. We discovered that 58% of the flood deaths in Texas over the previous six many years concerned automobiles.
The storm on June 12 in San Antonio was an instance. It was early morning, and drivers has poor visibility. Vehicles drove into floodwater with out seeing the danger till it was too late.
This text, initially printed July 5, 2025, has been up to date with the loss of life toll rising.
This text is republished from The Dialog, a nonprofit, unbiased information group bringing you information and reliable evaluation that can assist you make sense of our advanced world. It was written by: Hatim Sharif, The College of Texas at San Antonio
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Hatim Sharif doesn’t work for, seek the advice of, personal shares in or obtain funding from any firm or group that will profit from this text, and has disclosed no related affiliations past their educational appointment.
