Texas Hill Nation is understood for its landscapes, the place shallow rivers wind amongst hills and thru rugged valleys. That geography additionally makes it one of the most deadliest puts within the U.S. for flash flooding.
Within the early hours of July 4, 2025, a flash flood swept via a space of Hill Nation dotted with summer season camps and small cities about 70 miles northwest of San Antonio. Greater than 120 other people died within the flooding. The vast majority of them have been in Kerr County, together with greater than two dozen ladies and counselors at one summer season camp, Camp Mystic. Dozens of other people have been nonetheless unaccounted for every week later.
The flooding started with a heavy downpour, with greater than 10 inches of rain in some spaces, 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 Camp Mystic, confirmed how temporarily the river flooded: Round 3 a.m. on July 4, the Guadalupe River was once growing about 1 foot each and every 5 mins on the gauge, Nationwide Climate Carrier information displays. Via 4:30 a.m., it had risen greater than 20 ft. Because the water moved downstream, it reached Kerrville, the place the river rose even sooner.
Flood professional Hatim Sharif, a hydrologist and civil engineer on the College of Texas at San Antonio, explains what makes this a part of the rustic, referred to as Flash Flood Alley, so bad.
What makes Hill Nation so susceptible to flooding?
Texas as an entire leads the country in flood deaths, and by way of a large margin. A colleague and I analyzed information from 1959 to 2019 and located 1,069 other people had died in flooding in Texas over the ones six a long time. The following perfect general was once in Louisiana, with 693.
Lots of the ones flood deaths had been in Hill County. It’s a part of a space referred to as Flash Flood Alley, 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 temporarily when it floods. This can be a semi-arid house with soils that don’t absorb a lot water, so the water sheets off temporarily and the shallow creeks can upward thrust instant.
Flash Flood Alley is the sunshine inexperienced crescent. The background colours display the slope of the land, with purple the sharpest upward thrust.
Zhongyu Han and Hatim Sharif, GIS Utility: Flood Possibility Control, 2020
When the ones creeks converge on a river, they are able to create a surge of water that wipes out properties and washes away automobiles and, sadly, someone in its trail.
Hill Nation has noticed some devastating flash floods. In 1987, heavy rain in western Kerr County temporarily flooded the Guadalupe River, triggering a flash flood very similar to the only in 2025. Ten youngsters being evacuated from a camp died within the dashing water.
San Antonio, on the japanese fringe of Hill Nation, was once hit with a flash flood on June 12, 2025, that killed 13 other people whose automobiles have been swept away by way of top water from a fast-flooding creek close to an interstate ramp within the early morning.
Why does the area get such robust downpours?
One reason why Hill Nation will get tough downpours is the Balcones Escarpment.
The escarpment is a line of cliffs and steep hills created by way of a geologic fault. When heat air from the Gulf rushes up the escarpment, it condenses and will sell off a large number of moisture. That water flows down the hills temporarily, from many various instructions, filling streams and rivers beneath.
As temperature upward thrust, the hotter setting can dangle extra moisture, expanding the downpour and flood chance.
A excursion of the Guadalupe River and its flood chance.
The similar impact can give a contribution to flash flooding in San Antonio, the place the huge quantity of paved land and loss of up to date drainage to keep watch over runoff provides to the chance.
What may also be executed to give a boost to flash flood protection?
First, it’s vital for other people to know why flash flooding occurs and simply how briskly the water can upward thrust and waft. In lots of arid spaces, dry or shallow creeks can temporarily refill with fast-moving water and transform fatal. So other people will have to pay attention to the dangers and take note of the elements.
Bettering flood forecasting, with extra detailed fashions of the physics and water speed at other places, too can assist.
Probabilistic forecasting, for instance, may give a spread of rainfall situations, enabling government to organize for worst-case situations. A systematic framework linking rainfall forecasts to the native affects, similar to streamflow, flood intensity and water speed, may just additionally assist decision-makers enforce well timed evacuations or highway closures.
Schooling is especially very important for drivers. One to 2 ft of shifting water can wash away a automotive. Other folks might assume their vans and SUVs can undergo the rest, however fast-moving water can turn a truck and elevate it away.
Officers too can do extra to barricade roads when the flood chance is top to stop other people from using into hurt’s manner. We discovered that 58% of the flood deaths in Texas during the last six a long time concerned cars. The typhoon on June 12 in San Antonio was once an instance. It was once early morning, and drivers had deficient visibility. The automobiles have been hit by way of fast-rising floodwater from an adjoining creek.
This text, at first revealed July 5, 2025, has been up to date with the demise toll growing.
