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 means of an space of Hill Nation dotted with summer time camps and small cities about 70 miles west of San Antonio. Not less than 43 individuals died, and about two dozen ladies from one camp had been nonetheless unaccounted for the next day, officers stated. Greater than 200 individuals needed to be rescued, and extra rain was forecast by means of 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 shortly 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 reveals. By 4:30 a.m., it had risen greater than 20 ft.
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, referred to as Flash Flood Alley, so harmful.
What makes Hill Nation so liable 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 subsequent highest whole was in Louisiana, with 693.
A lot of these flood deaths have been in Hill County, an space referred to as Flash Flood Alley. It’s a crescent of land that curves from close to Dallas all the way down to San Antonio after which westward.
The hills are steep, and the water strikes shortly when it floods. It is a semi-arid space with soils that don’t absorb a lot water, so the water sheets off shortly 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 shortly flooded the Guadalupe River, triggering a flash flood just like the one in 2025. Ten youngsters being evacuated from a camp died within the speeding water.
San Antonio, on the japanese 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 sturdy downpours?
One purpose 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 a whole lot of moisture. That water flows down the hills shortly, from many alternative instructions, filling streams and rivers beneath.
As temperature rise, the hotter ambiance can maintain extra moisture, growing 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 regulate runoff provides to the chance.
What will be carried out to enhance flash flood security?
First, it’s vital for individuals to know why flash flooding occurs and simply how briskly the water can rise and move. In lots of arid areas, dry or shallow creeks can shortly replenish with fast-moving water and turn 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 areas, also can assist.
Probabilistic forecasting, for instance, can present a variety of rainfall eventualities, enabling authorities to arrange for worst-case eventualities. A scientific framework linking rainfall forecasts to the native impacts, comparable to streamflow, flood depth and water velocity, might additionally assist decision-makers implement well timed evacuations or street closures.
Training is especially important for drivers. One to 2 ft of shifting water can wash away a automobile. Folks might imagine their vehicles and SUVs can undergo something, however fast-moving water can flip a truck and carry it away.
Officers also can do extra to barricade roads when the flood threat is excessive to stop 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 chance till it was too late.
This text, initially printed July 5, 2025, has been up to date with the dying toll rising.
This text is republished from The Dialog, a nonprofit, impartial information group bringing you details and reliable evaluation that will help you make sense of our complicated 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 may profit from this text, and has disclosed no related affiliations past their tutorial appointment.
