Why were the central Texas floods so deadly?

Vox

07-07-2025

is a correspondent at Vox writing about climate change, energy policy, and science. He is also a regular contributor to the radio program Science Friday. Prior to Vox, he was a reporter for ClimateWire at E&E News.
At least 90 people have died in central Texas in extraordinary floods, the deadliest in the Lone Star State since Hurricane Harvey killed 89 people.
A torrential downpour started off the July 4 weekend with several months' worth of rain falling in a few hours, lifting water levels in the Guadalupe River as high as 22 feet. Among the dead are 27 children and counselors at a summer camp near Kerrville in Kerr County. One adult at the camp may have died trying to rescue children. More people are still missing, and more rain is in the forecast.
The storm arose from the fading remnants of Tropical Storm Barry, which formed on June 28. It was well ahead of schedule for the typical second named storm of the Atlantic hurricane season, which usually forms in mid-July. The weather system parked over Texas where it converged with a band of moisture moving north, forming thunderstorms that squeezed out a torrential downpour.
With its topography of hills and rivers as well as a history of sudden downpours, this region in Texas has been dubbed 'flash flood alley.' Kerrville itself experienced a deadly flood in 1987 when the Guadalupe River received 11 inches of rain in less than five hours, raising water in some portions by 29 feet. The flood killed 10 people.
But there were several factors that converged to make this storm so deadly — and not all of them had to do with the sheer amount of rain. Here are some things to know about disasters like this:
Texas isn't in the tropics. How did it get hit so hard by a tropical storm?
Kerr County, population 54,000, is a couple hundred miles inland from the Gulf of Mexico, but it has a history of tropical storms and hurricanes passing through the region on occasion. So the leftovers from Tropical Storm Barry reaching the area isn't too surprising. Scientists, however, are still trying to find out how storms that are powered by warm ocean water continue to get energy over land.
As average temperatures rise due to climate change, air can retain more moisture, which means when storms occur, there's more water falling out of the sky, turning roads into rivers and submerging the landscape.
Did something go wrong here with the forecast or disaster warnings?
Ahead of the Texas floods, the Texas Division of Emergency Management activated its emergency response system on July 2 in anticipation of major floods, including mobilizing water rescue squads, helicopters, and road-clearing equipment. On July 3, the National Weather Service issued a flood watch. (NPR has a very useful timeline of the planning and response to the floods.)
But as the watches turned to warnings, they revealed gaps in the communication system. There are spots along the Guadalupe River that don't have flood warning sirens, including Kerr County. Officials there contemplated installing a flood warning system, but it was rejected for being too expensive.
Text message alerts did go out, but they were sent in the middle of the night after the July Fourth holiday, when many people were camping or traveling in unfamiliar places. Parts of the county also have spotty cell service. And residents who did get the alerts weren't sure what to do about them, whether to stay or evacuate, until the water levels were perilously high.
The National Weather Service this year has lost 600 employees between layoffs, buyouts, and retirements spurred by the Trump administration's 'Department of Government Efficiency.' That included Paul Yura, the warning coordination meteorologist at the National Weather Service Austin/San Antonio office, which is responsible for Kerr County. However, National Weather Service staff said the office was operating normally during the floods and wasn't dealing with a staff shortage.
In general, natural disasters are killing fewer people over time. There are a lot of reasons why, like stronger building codes that can better resist fires, floods, and earthquakes.
One of the most important lifesaving trends is better warning systems ahead of huge storms. Improvements in observations, a growing understanding of the underlying physics, and advances in computer modeling have led forecasters to build up their lead time ahead of severe weather. Researchers are even starting to get more forewarnings about volcanic eruptions and earthquakes.
But warnings are only effective if people have the knowledge and the tools to react to them. During floods, people often underestimate currents and try to cross dangerous submerged areas. 'Purposely driving or walking into floodwaters accounts for more than 86% of total flood fatalities,' according to a study of flood deaths in the US between 1959 and 2019.
It is possible to protect lives against the forces of nature, but it requires a lot of parts working together — planning, infrastructure, forecasting, alerts, and evacuations.
Are floods getting more difficult to predict?
Not necessarily, but the baselines are changing.
Most assessments of flood risk are based on historical data. Local, state, and federal agencies can map out high watermarks of the past and show which properties might be at the greatest risk. But at best, these maps are conservative estimates; they don't show the full potential of where water can reach. Often, flood maps aren't revised regularly and don't take into account how the risk landscape is changing.
For instance, more construction in an area can lead to more impervious surfaces that retain water or shunt it toward a certain neighborhood. Losing natural watersheds that normally soak up rain can increase the probability of floods. Overdrawing groundwater can cause land to sink.
In coastal areas, rising sea levels are increasing the reach of coastal flooding, while rainstorms inland are pouring out more water. Disasters can also compound each other. A major wildfire can wipe out trees and grasses anchoring soil, leading to floods and landslides when the rain comes, for example.
Inflation, growing populations, and rising property values mean that when floods do occur, they extract a much bigger price from the economy. Kerr County's population has grown about 25 percent since 2000.
As a result, when it comes to floods, many people don't even realize that they're at risk. And even in the wake of a major inundation, the lessons are quickly forgotten.
One analysis showed that people buy more flood insurance after a major flood recedes, but gradually, they let their policies lapse, returning to the baseline insurance rate in three years in some cases. That's why one of the biggest challenges in disaster risk reduction is simply trying to get people to understand that bad things can happen to them and they should prepare.