Texas flood damage could top $3 billion for 2015

A fresh analysis found 2015 floods could cost Texas more than $3 billion. See photos of the historic floods that swamped Texas this year and in years past... A fresh analysis found 2015 floods could cost Texas more than $3 billion. See photos of the historic floods that swamped Texas this year and in years past... Photo: Brett Coomer, Houston Chronicle Photo: Brett Coomer, Houston Chronicle Image 1 of / 284 Caption Close Texas flood damage could top $3 billion for 2015 1 / 284 Back to Gallery

Widespread flooding in 2015 could cost Texas upwards of $3 billion largely from damage to soaked roads and public infrastructure, according to a fresh analysis.

Last weekend Texas weathered its second record-breaking rainfall event of the year, when three storm systems converged and flooded cities statewide. Hundreds of roadways ended up underwater, either soaking in a standing flood or bearing a raging current. That does damage.

RELATED: Interactive map shows what weekend rains did to Houston

"These kinds of [disasters] are particularly nasty because, with that kind of infrastructure damage, tax payers are going to get stuck with the cost," said Chuck Watson, director of research and development at Kinetic Analysis Corp., a disaster impact modeling firm in Maryland.

He produced the $3 billion estimate—which mirrors the boost state law makers gave to transportation spending this year--with Kinetic's intricate databases and computer models, thousands of National Weather Service reports, news reports and insurance data.

For context: of $45 million in damages done when May storms swamped Houston, $25 million was to public infrastructure, $4.5 million was to buildings and $15 million was for cleanup.

On Friday and Saturday, floods covered 330 spots on 232 state-maintained roads, according to the Texas Department of Transportation. Some of those spots were really big—like a nearly 12-mile length of Interstate 45 in Navarro County that sat submerged for an entire day.

And hundreds more city and county roads suffered similarly. In Austin, the only city with data readily available Tuesday, high water covered 66 spots on city roads.

RELATED: Floods cause more than 100K gallons of wastewater to spill

"More than likely it's going to be some damage there with the water having sat for as long as it did," said TxDOT spokesman Mark Cross. "But we won't know completely until things dry out."

He said a final damage tally is months away.

A road that's been saturated to its bed will probably crack, buckle and form potholes in later months. Existing cracks and potholes will grow larger. In fast-moving water, road embankments can get washed away, street signs can topple and electrical equipment, like traffic lights, can fry.

Waterborne debris can clog bridge joints, causing the structure to buckle. Exceptionally strong currents can even wash away pavement or concrete road linings.

But FEMA's National Flood Insurance Program, almost the only high water insurance available in the county, doesn't cover damage to public infrastructure like roads, an agency spokesman said. The dozens of counties declared disaster areas last spring and this fall will get federal relief money, but how that can be applied remains unclear.

RELATED: Federal aid for flood victims tops $11 million

Watson said $3 billion for a year's worth of disaster costs is not shocking, but records from the National Climate Data Center suggests 2015 could have brought Texas' costliest year of flooding on record.

The federal agency lists weather disasters with an estimated repair cost exceeding $1 billion in 2014 dollars; records show severe floods dealt $1 billion damages in 1998 and $2 billion in 1994. Texas and neighboring states split the check on $2 billion and $3 billion in expenses from floods in 1990 and 1983, respectively.

Watson cautioned that his figure includes a wide range of projected costs to the state economy, while the NCDC reports only hard damage. Still, 2015 has been a wet, expensive year.

RELATED: May 2015 is now Texas' wettest month on record

"What was exceptional this year, in Texas and across the southeast, was how widespread the floods were," Watson said, noting that many Southern states, including Texas, shattered monthly rainfall records this year.

When he's not an economic analyst, Watson sits on a scientific review panel for the U.N.'s Intergovernmental Panel on Climate Change, which released its chilling fifth report in 2013. (Watson holds a bachelor's degree in electrical engineering, a master's in geophysics and a PhD in economics.)

He said he's leery of frequent hastily-drawn links between weather disasters and climate change, which remains a nebulous concept. Because the oldest detailed weather records date back just a century—hardly a second in Earth time—Watson said it remains unclear if recent calamitous events are part of normal long-term weather cycles or a steady trend towards a warmer planet.

RELATED: Study: Climate change could ravage Texas - 10 key outtakes

"We're kind of at that tipping point from a data standpoint, where you can't tie in any particular event, but it does seem like the frequencies are changing," he said. "We're starting to see changes in extreme events. We're getting different kinds, and we're getting more of them."

Forecasters expect heavier-than-average Texas rains to continue through early 2016 thanks to El Niño, a recurrent global weather pattern that brings extra moisture to the Lone Star State, and this year has grown to the strongest event on record. It should peak in early winter.

State climatologist John Nielsen-Gammon said 2015 will likely end up the wettest year on record for many northern parts of Texas.