When water hits like a tornado: The violent force of flash flooding
It looks like a wall of water. But it hits like a column of freight trucks. Flash floods carry thousands of tons of force. Here’s what makes them so destructive.
In Texas, this year is on pace to be one of the deadliest flooding disaster years since the 1900s. AccuWeather’s Leslie Hudson has more.
When the Guadalupe River surged more than 26 feet in less than an hour on July 4, it wasn’t just a flood, it was a force of nature tearing through central Texas. The river carried away vehicles, homes and lives, leaving behind wreckage that looked more like the aftermath of a tornado than a thunderstorm.
Flash floods can look deceptively calm before turning catastrophic. In the Guadalupe River basin, thunderstorms dumped more than 10 inches of rain, overwhelming the system and triggering a wall of water that moved with crushing speed.
A river on the move
At its peak, the Guadalupe River was moving an estimated 150,000 cubic feet of water every second—more than 4,200 tons. Gregory Waller, a service coordination hydrologist with the West Gulf River Forecast Center, compared it to a column of 18-wheelers barreling downstream. “We had 150,000 of these cubic feet going through,” Waller said. “You could equate it like a column of 18-wheelers coming down that river system, knocking everything out.”
But it wasn’t just water. “It picks up debris,” Waller said. “It picks up a log, which becomes a medieval battering ram. It picks up a car, a vehicle, a house — that creates more surface area and more force.”
(Photo credit: Center Point Volunteer Fire Department/Facebook)
Fast-moving water is about 800 times denser than air. Just a few feet of floodwater can exert more pressure than an EF5 tornado. “They're both catastrophic even though the damage looks similar,” Waller said. “A tornado is 100+ miles an hour, 200+ mile an hour winds, but only for a few minutes. We're talking about a volume of water that even in a fast-responding river system, it's two to three hours to go up, two to three hours to come down.”
That longer exposure means more time for damage to occur, more structures to be compromised, and more lives to be at risk.
More force than a tornado
“Every cubic foot of water weighs 62 pounds,” Waller said. “You get to 1,000 cubic feet per second moving through an area... you're talking about 62,000 pounds of force.” And during some of this summer’s deadliest flooding, the total water weight reached 7.5 million pounds per second.
Volunteers work to clear fallen trees on July 12, 2025, in Hunt, Texas. (Photo by Brandon Bell/Getty Images)
Search and recovery crews use a large excavator to remove debris from the bank of the Guadalupe River on July 9, 2025, in Center Point, Texas. (Photo by Jim Vondruska/Getty Images)
And as Waller illustrated, floodwaters don’t just push — they carry. Logs, cars, propane tanks, even houses become part of the current, compounding the danger with each new object. The result is damage that can look indistinguishable from a high-end tornado, but stretched across an entire town.
Why the danger is growing
AccuWeather Vice President of Forecast Operations Dan DePodwin and AccuWeather Climate Expert Brett Anderson discuss the top headlines related to climate change in the July 11 edition of Climate In The News.
Flash flooding has always been a summertime threat, but the risks are evolving. “Warmer air holds more water vapor,” said Brett Anderson, AccuWeather climate expert. “More water vapor means a higher potential for heavy rainfall events.”
“We can't necessarily say that one specific flood is caused by climate change,” said Dan DePodwin, AccuWeather’s Senior Director of Forecasting Operations. “But we can say they're amplified by it. They're more intense, more frequent.”
In central Texas, that amplification was made worse by land conditions. “This area was under severe to extreme drought just before the floods,” DePodwin said. “The soil was very hard and dry... like raining onto concrete. It had nowhere to go other than down the river very quickly.”
A search and rescue worker has his dog sniff through debris looking for any survivors or remains of people swept up in the flash flooding on July 7, 2025, in Hunt, Texas. (Photo by Jim Vondruska/Getty Images)
Sergio Sanchez walks through debris while assisting with search and rescue efforts on the banks of the Guadalupe River on July 06, 2025, in Center Point, Texas. (Photo by Brandon Bell/Getty Images)
Nationwide, the trend is expanding. “We’re seeing a greater amount of land area being affected by these extreme rainfall events across the entire U.S.,” Anderson said. “There’s a projected 20 to 40 percent increase in rainfall events in the Tennessee Valley and parts of New England.”
According to NOAA, 2025 already ranks as the third-deadliest flash flood year since the Great Flood of 1913, and the year isn’t over.
Additional reporting by AccuWeather's Leslie Hudson
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