In central Texas, flash flooding killed more than 85 people, and officials are searching for dozens of people still missing.
State officials say the Guadalupe River rose 26 feet in 45 minutes. And Rice University professor of civil and environmental engineering Avantika Gori said that this hilly, rural area in Texas is conducive to dangerous flooding; once the waters start, they just cascade down the landscape. Additionally, rain fell fast and heavily.
“With that extreme level of rainfall, you can get really raging rivers and basically like a wall of water,” Gori said. “This is the Texas Hill Country. The topography is highly sloped. So the water hits the ground and just rushes downstream.”
5 questions with Avantika Gori
Why does this part of Texas get such heavy, prolonged rainfall?
“Spring and summer is really the peak season for heavy thunderstorms in central and coastal Texas. And that’s really because the warm waters of the Gulf are a really potent moisture and fuel source.
“As was the case with this storm, so it was pulling the remnants of a previous tropical system in the Gulf and that very, very high level of moisture in the water acted as fuel for this storm that allowed such intense rainfall.”
What warnings were given to residents before the flooding started? We know the National Weather Service sent warnings, but those depend on cell phone access and service.
“First of all, cell reception is not great. Second of all, people in rural counties may not all have cell phones. And then I think the third is this area of Texas frequently has flash floods. Many are not severe, and so residents may not have necessarily understood the difference between a run-of-the-mill flash flood watch and this type of extreme warning.”
Many Texas residents found out about the impending flooding as the water was already arriving. Are you surprised by that? Or is that how things usually happen?
“I think it’s important to emphasize that this was an extremely rare event. So usually even in this area with, you know, it’s a hill terrain, it’s not common to have such extreme flash floods as we saw.
“So, I do think warnings in the past have been more successful because there was more lead time for residents to kind of get to higher ground or safety. Whereas in this case, there was a very short lead time. And as you’re saying, many were caught unaware and only found out when they saw the water levels rising themselves.”
What can we learn about communicating the risk of floods going forward?
“More information is going to come in the next days and weeks, and there’s gonna be many analyses about this event. But I think one takeaway is that there needs to be a better system in place for these really high emergency events. And just relying on text messages is not sufficient.”
What are some options for a better system?
“One option that the county had looked into before was implementing sirens, which could be a cost-effective option, especially in communities that are relatively small in size. So that could be one option. Others could be developing a system for contacting the relevant community organizations that can help spread the word more easily.”
This interview has been edited for clarity.
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Thomas Danielian produced and edited this segment for broadcast with Catherine Welch. Grace Griffin produced it for the web.
This article was originally published on WBUR.org.
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