Houston – New research from Rice University is raising new concerns about flood risk across Houston, suggesting some neighborhoods long considered safe may still be vulnerable.
The study comes 10 years after the Tax Day Flood, a storm researchers say is often overshadowed by Hurricane Harvey, but remains one of the most dangerous scenarios for the region.
Researchers at Rice’s Center for Coastal Futures and Adaptive Resilience say the Tax Day flood is especially concerning because of how quickly it developed.
“Houston really should take possible storms as seriously as probable storms,” said co-director Dominic Boyer.
Unlike hurricanes, which come with days of warning, the Tax Day storm dumped nearly two feet of rain overnight in parts of the region, catching many off guard.
Researchers say that kind of fast-moving storm could be even more dangerous today.
What the new maps show
Using advanced modeling, researchers simulated what would happen if a Tax Day-level storm hit different parts of Houston today.
They found that shifting the storm just miles could dramatically increase the number of homes impacted.
In one example, about 3,600 homes would have flooded in a Clear Creek scenario—but if the storm’s center shifted, that number jumps to more than 13,000.
In denser areas like Hunting Bayou, nearly half of homes in the watershed could see flooding.
“This could happen overnight without a whole lot of warning,” said co-director Jim Elliott.
A “dangerous illusion” about flood risk
Researchers say one of the biggest concerns is a widespread misunderstanding about who is at risk.
“Our data shows a massive blind spot. 92% of at-risk homes do not have flood insurance coverage,” said researcher Yilei Yu. “It’s a very dangerous illusion.”
Many homeowners rely on FEMA flood maps, but experts warn those maps don’t tell the full story.
“Floodwaters are not going to respect the boundaries,” Elliott said. “They’re going to extend beyond.”
In fact, during Hurricane Harvey, about 75% of flooded homes were outside designated flood zones.
A Meyerland family’s reality
For one Meyerland family, that risk became reality.
Michael and Freda Wadler say their home had never flooded when they bought it 30 years ago.
Then, in less than a decade, it flooded three times, during the Memorial Day flood, the Tax Day flood, and Hurricane Harvey.
“I don’t know if anybody’s really safe in Houston, you never know,” Michael Wadler said.
Living with the anxiety of flood season
The couple says flood season used to bring constant stress—not just for them, but for their family.
“You don’t realize the post-traumatic stress that you’ve got,” Wadler said. “It was always nerve-racking.”
Even their children would call and warn them when storms were approaching.
Now, their home is being elevated six feet above ground with the help of a FEMA grant.
“It feels like a miracle. It’s long overdue,” Wadler said.
The change is already making a difference.
With more intense storms, rapid development, and aging infrastructure, researchers warn that risk is growing.
“We’ve had multiple ‘500-year’ events in just a few years,” Boyer said. “We’re moving outside the boundaries of prediction.”
What homeowners should do
Researchers urge residents not to rely solely on flood maps, and to take steps to understand their individual risk.
“Do not rely solely on FEMA flood maps,” Elliott said. “Even if you think you’re outside the floodplain… think seriously about protection.”
That includes considering flood insurance and using new tools, like Rice’s interactive maps, to assess potential risk.
You can explore the interactive flood simulation maps from Rice University here.