Guadalupe River surged 20 feet in 95 minutes amid deadly Texas flooding

Though the Guadalupe River basin high in the Texas Hill Country is known for its flooding danger, the lack of a modern flood warning system sent campers and others in low-lying areas scrambling with little sounding of alarms.

Local emergency officials and the National Weather Service get their information from four gauges along the Guadalupe River upstream from Kerrville, where the flash flooding that killed at least 68 people occurred on July 4.

One of four gauges on the river failed, likely because of the wall of water that surged downstream in the early hours of Friday. In places, water rose 40-feet above the streambed. As crews raced to respond to low areas along the river, and campers and others fled, a review of the sensor data shows the river grew in height, width and speed with sudden force.

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No design, dam or flood control project is going to solve the threat posed by the uppermost part of the river basin.

“You cannot engineer yourself around the Guadalupe,” said Phil Bedient, the director of Rice University's SSPEED Center, who has spent decades designing flood protection and prediction systems. “This one is crying out for a warning system.”

State and local officials rely on those gauges to monitor the Guadalupe, along with a more antiquated system that warns drivers of high water at low parts of state roads and tracks rainfall.

Along Texas 39 and FM 1340, the Texas Department of Transportation has sensors that monitor when the roads are topped by floodwaters. All told, fewer than 35 sensors along roads or the riverbank can activate flashing lights or tell emergency officials where water is encroaching and the river is flooding.

Kerr County Judge Robert Kelly on Friday called the Guadalupe “the most dangerous river valley in the United States,” as rescuers scoured low-lying areas for victims.

“He is probably right about that,” Bedient said.

The reason is three-fold, Bedient said: Intense storms, steep slopes and rapid movement of those storms into the low-lying areas in the Hill Country.

“​​When you are dealing with that, all bets are off,” he said. “It is a raging torrent, and it has nothing to do with water getting into the ground.”

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That is precisely what gauges along the Guadalupe indicate happened on Friday. As the rain strengthened and stalled over Kerr County, the north fork of the Guadalupe west of Hunt surged. The river went from two feet at 2 a.m. to nearly seven feet in an hour. The gauge topped out at 19.5 feet around 5 a.m.

“These things invariably occur in the middle of the night,” Bedient said.

The water level grew progressively higher as it flowed downstream. The next monitor, along the main river at Hunt, rose 20 feet in roughly 95 minutes, topping at 37.5 feet just after 5:00 a.m.

The river might have risen even more, but the monitor stopped providing updates at 5:10 a.m., before coming back online around 3:45 p.m. on Saturday.

Sensors downstream peaked around 7 a.m., and by 11 a.m. levels at all the upper Guadalupe sensors were dropping back to more common levels during rains.

“It just rips,” Bedient said of the fast rise and fall. “And because it rips… there should be an effort to do a better gauging job up on the Guadalupe.”

That is especially true near the origin of the river in Kerr County, he said, where the speed of the flooding is predictable, but gives officials scant time to spread the word. Moments can make the difference.

“Get to high ground," Bedient said. “These are steep watersheds but you can get to high ground. ​​You just have to get 25 feet higher.”

Damage throughout the basin

Death and injury from flooding is a constant along the Guadalupe, with seven of the nine counties having at least one fatality from a flash flood, river flood or heavy rain in the past 30 years. Since Jan. 1, 1996, 50 people have died and 4,439 have been injured in flooding events in the counties through which the river basin runs. Hays County, the most populous, leads the way with 15 deaths, 13 of which happened during heavy flooding in Wimberley on Memorial Day weekend in 2015.

Throughout the river basin, the majority of fatalities come along roadways when people travel into high water, officials said.

Though the topography and risk remains high for devastating flooding, Kerr County has avoided casualties in recent years. Between 1996 and June 2025, the county reported three deaths and 22 injuries during 98 flooding events and heavy rains.

In 1987, during what is now the second-worst flooding along the river, 10 campers were killed when the last bus leaving an inundated campground near Comfort was unable to cross a low point near the riverbank.

Led by counselors, 43 adults and children tried to form a human chain and make it to higher ground, but many were soon swept away. A frantic rescue ensued, with helicopter pilots inching lower into the trees to pluck youngsters from the branches. One teenager died, falling from an attempted helicopter rescue.

As with Friday, Comfort was complicated because the campers were in low-lying areas around the river.

“They are down by the river because that is where they can swim and camp,” Bedient said of the popular recreation areas, many on private land with their own access roads.

Early work on early warning

The Comfort tragedy led to the installation of the current monitoring stations, while other incidents in the basin have led to even more planning – but so far no major changes in Kerr County.

Following the deadly 2015 flooding on the Blanco River in Wimberley, officials in the Guadalupe Valley explored the need for more sensors that could create an early warning system.

“We literally have minutes or hours before something is going to happen based on a rain event,” Kerr County Engineer Charlie Hastings said during a Feb. 3, 2021, discussion of a new system.

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The system would be like those used for years in Harris and Bexar counties, which combines weather data, gauges along waterways and emergency management warnings. Put together, the forecasts and real-time information give officials a way to alert people as the risk of rising waters increases.

The systems, which Bedient has helped develop, have saved lives and property in specific locations, such as the Texas Medical Center. Investment in them, however, has not been prioritized in less populated areas, including Kerr County.

Kerr County’s preliminary plan for a warning system, at a cost of between $750,000 and $1 million, was completed by mid-2017. During that 2021 discussion, then-county commissioner Jonathan Letz said the efforts to find state funding later that year and in 2018 ran into competition with another storm – Hurricane Harvey.

“All the money went to that one event, which made sense,” he said.

The plan, now part of a $9.5 million system along the 230-mile river to the Gulf of Mexico, is ranked 23rd in terms of priority in the state’s 2024 flood plan.

Bedient said it is likely, as Comfort led to investment, so will Friday’s flooding.

“I would be very surprised if there is not a major effort,” he said.