A New Way To Predict Floods Nationally Started In Central Texas' 'Flash Flood Alley'
New technology developed here in Austin promises to give advanced warning for floods, but what exactly would that mean for first responders struggling to rescue people? A look at recent flooding in Central Texas shows how a project to provide real-time flood prediction software on a national scale could help.
It started with a call from the “Old Timers Network,” which is what Wimberly City Manager Don Ferguson calls the ranchers and farmers that live up the Blanco River from his town.
“We have a number of folks upstream who are good neighbors and they keep a close eye,” Ferguson says. “And they pick up the phone and call us when they get extremely heavy rainfall.”
That day it was a rancher. He was getting hit hard by a storm, and he phoned to say Wimberley should expect flooding.
“Then we got a return call, not long after, saying that he’s seeing water go where he’s never seen it going before,” Ferguson says.
With that warning, emergency responders in Wimberley took action.
“About two and a half to three hours before the water came into Wimberley we had streets evacuated, we had door to door evacuations and we had started asking for swift water resources,” he says. “We lucked out”
Except, when you think about what happened next, luck is not the first word that comes to mind. Unknown to the townspeople a second river, the Little Blanco, had also flooded. When the waters from that river joined the Blanco it brought a wall of water over 50 feet high down on the community. The flood took 11 lives, and 350 homes were damaged or destroyed.
Driving around months after, the damage is still visible. Bare slab foundations sit where houses were swept away. Hundred-year-old trees, stripped of their bark, stick out at odd angles from the flood path or lay completely flat – like they were stomped down along the river.
“This is the area we ran to that night as the waters were starting to move in. A lot of these homes had sleeping bags on top of them because people had crawled out, had ridden out the flood on top of their homes,” Ferguson says, behind the wheel of his pickup truck.
Even Ferguson and his team got stuck on the wrong side of a low water crossing, at what he calls “the infamous Schidt Creek.”
They were evacuating homes when river waters backed up on the creek. Stuck on one side, Ferguson stayed in his truck until the light of day revealed the devastation.
“I had an employee who got pinned on the upper end. And he came down to me and his first words were, ‘There’s nothing left…about halfway up the road it’s all gone.’ And it was,” he says. “There [were] some beautiful homes that had been there for years, and they literally were gone. I’m not talking about broken up on sight. I’m talking about gone. It was staggering.”
Like Ferguson, UT hydrologist and civil engineering Professor David Maidment says, crazy as it sounds, the town did kind of luck out. It goes back to that rancher who called in the warning.
“I mean just imagine if that guy hadn’t have called? They ordered a thousand people out of harm’s way?” Maidment says. “It’s a sobering thought as to the alternatives, huh?”
He wants to take some of that uncertainty out of the equation. He’s helped create a new flood forecasting system that gives faster more detailed information, and says he was was compelled to initiate the project in the wake of the 2013 Halloween flooding in Onion Creek.
The system works as a tool that predicts weather and flooding, but, unlike current systems, it relies on a lot of different disciplines. Hydrology, which he says connects “rain in the sky with water on the ground,” and geography, which connects “water on the ground with flow in the streams.” Supercomputing crunches the datasets and runs the models.
“We haven’t used supercomputing for hydrologic forecasting before,” he says. “This is the first time that’s been done.”
Right now, the National Weather Service predicts flooding at a limited number of points along waterways. It takes up to an hour to run those models. In Wimberley, for example, there was just one forecast point that was in town.
Maidment says the new system will have 130 forecast points upstream. That kind of detail gives insight into small creeks and rivers like the ones that gave Wimberley trouble, but the system isn’t just for Central Texas. It’s going national.
“We’ve got now the capacity to measure about one one-hundredth of the number of streams that exist in the country. In other words for every one that we measure, there are 99 we don’t know about and, basically, we’re going to calculate the other 99 instead of having to measure the whole lot,” he says.
Maidment’s project will start predicting floods across the country next May. It will be operated out of the new National Water Center recently opened in Tuscaloosa, Alabama. The Town of Wimberley's also getting some added help.
“We’ll be back, we’ll be back stronger than ever,” says Ferguson.
He says more river gages are going in on the Blanco River. But, he still plans to pick up the phone whenever he gets a call from his Old Timers Network.