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The very qualities that draw people to the beautiful Texas Hill Country — its rolling terrain, limestone formations and lazy rivers — also make the area especially dangerous during heavy rainstorms.
“So when rain happens, water flows at a really fast speed,” said Nasir Gharaibeh, professor of civil and environmental engineering at Texas A&M University.
Gharaibeh studies flash floods, and he said the key word is “flash.” These things happen really fast.

"We are finding that flash flooding is really the most lethal type of flooding. Generally speaking, nationwide, about 70% of fatalities in flood events happen in flash flood events," he said. "About 40% of flash-flood events that happened in Texas happened in this region."
That's why Central Texas is known as flash flood alley.
Gharaibeh said storms like what residents faced on the Fourth of July develop quickly in the area.
“The key thing needs to be a better warning system,” he said.
Kerr County Judge Rob Kelly said during a press conference that the county doesn’t have a warning system and that local officials were caught off guard.
“We didn’t know this flood was coming," Kelly said. "Rest assured, no one knew this kind of flood was coming.”
Rick Spinrad, the former head of the National Oceanic and Atmospheric Administration, or NOAA, pushed back on Kelly’s statement: "The Weather Service did their job, according to standard practice and protocol in terms of getting out forecasts, getting watches and warnings out in the sort of timeframes that make sense going back to Wednesday and then into Thursday."
Spinrad said that recent layoffs to the National Weather Service (NWS) by the Trump administration have impacted local weather forecasting. But warnings were issued, he said.
"Weather Service is down to probably about 25% on its staffing, including at the two weather forecast offices directly involved in the flooding on the Guadalupe River in San Angelo and Austin, San Antonio."
Secretary of Homeland Security Kristi Noem criticized NOAA for its performance leading up to the flood.

“We know that everybody wants more warning time, and that's why we're working to upgrade the technologies that have been neglected by far too long to make sure that families have as much advanced notice as possible," Noem said at a news briefing in Kerrville on Saturday.
Spinrad questioned that assessment.
“I do not know what she's talking about," he said. "With respect to antiquated equipment, NOAA and the National Weather Service have very aggressive recapitalization programs for things like the weather radars around the country. NOAA is always updating and improving its use of computer models, looking to the applications of artificial intelligence."
He said the only thing that's changed are the layoffs. "I think we're starting to see the consequences of that, in terms of the horrible developments in Texas this weekend.”
So what went wrong?
Nim Kidd, chief of the Texas Division of Emergency Management, said messaging is just one aspect of alerting the public during an emergency.
“There can be all kinds of alert systems that are sent. General messaging was sent early" ahead of the recent flooding, Kidd said. "Some urgent warnings were sent at various times. But just sending the messages is not the same as receiving the message."
Even more crucial is "having a plan to do something when you receive the message, and the ability to implement that plan," he said.
Kerri Stephens, an organizational communication and technology professor at the University of Texas at Austin, studies how Texans deal with flash-flood risk.
She said many people, especially newcomers to the area, don’t understand how deadly flash floods are.
“People want the beauty of the river. They want those huge trees, and they just don't understand what a 100-year floodplain is or a 500-year floodplain," she said, referring to areas that are more prone to flooding. "And they don't understand that there's some risk every single year that they live in a geographic area.”
Stephens added that it's hard for people to imagine that a dry creek bed one day could be a raging river the next. She said aggressive public awareness campaigns that educate residents and visitors about the dangers of flash flood alley are necessary.
“In Texas, the saying is typically that we are in a perpetual state of drought, occasionally interrupted by flood," she said. "So the fact that we have this need for water yet when we get a lot of water in a short period of time, it's absolutely devastating. That's a hard type of risk for people to grasp.”