What makes flash flooding so dangerous in the Texas Hill Country?

AccuWeather

A roughly 275-mile-long stretch of terrain along I-35 is one of the most flood-prone regions in the U.S., but why? AccuWeather's Leslie Hudson takes a look.

Transcript

00:00The Texas Hill Country has captured the world's attention this week as the

00:06catastrophe along the Guadalupe River continues to unfold. This area has set

00:12some of the US rainfall records. From San Antonio to Dallas, Texas, this roughly

00:17275 mile stretch of terrain that runs along Interstate 35 is known as one of

00:23the most flood prone regions in the country. With the Balcones escarpment or

00:28this rise in the topography that we see right along the I-35 corridor, it tends

00:33to enhance many of these storm systems. The weather and landscape in South

00:36Central Texas work in tandem to create slow-moving perfect storms that often

00:41produce rapid flooding events, according to Lower Colorado River Authority

00:46meteorologist Bob Rose. We're going from the coastal plains right into the hill

00:50country. There's a rise of at least about 500 feet in elevation, but along with

00:55that you have a lot of your hills and valleys that go along with that type of

01:00topography. Texas's flash flood alley has a long and storied history of flash

01:05flooding disasters from flooded streets in Waco in the 1930s to raging rivers in

01:11Dallas in the 1960s to June 2025, where at least 13 people were killed in San Antonio

01:18from flash flooding. And these hills don't contain a lot of soil. They're very

01:23thin soil. So when rain does hit them, not much of it gets absorbed. Rose says warm, moist air

01:28from the Gulf helps fuel storms as well, giving them ample moisture to dump lots of rain and

01:34a short amount of time across the dusty Texas soil. By putting more people here, more

01:40development now, there's less place for the water to go. So we'll run off and all of that

01:44together does dramatically increase the risk for flash flooding. Floods here can happen so

01:50quickly that it just doesn't give you a lot of time to react. For AccuWeather, I'm Leslie Hudson reporting.

Category

Transcript

Recommended