The holiday and the type of hazard have changed, but once again fast-growing Texas is seeing outsize (and tragic) impacts from extreme weather events.
On Labor Day weekend in 2011, the disaster was heat- and drought-fueled fires that whipped through the exurbs east of Austin, most of which The holiday and the type of hazard have changed, but once again fast-growing Texas is seeing outsize (and tragic) impacts from extreme weather events.
On Labor Day weekend in 2011, the disaster was heat- and drought-fueled fires that whipped through the exurbs east of Austin, most of which didn’t exist just a few decades earlier.
Now, Houston is flooded and Hays County, west of Austin, is still in search and rescue mode after Memorial Day weekend flash flooding swelled rivers to record heights, inundating fast-growing riverbank towns and sweeping away a home packed with vacationers. (A Mexican border town and parts of Oklahoma are also reeling.)
What connects wildfire and raging waters?
Somewhere, deep in the statistical noise, there is a contribution from the global buildup of heat-trapping gases changing the climate system.
Among the clearest outcomes of global warming are hotter heat waves and having more of a season’s rain come in heavy downpours. But the picture gets murky, indeed nearly insoluble, at the scale of states or smaller regions. There’s more on this below from the Texas state climatologist and others. The bottom line is there’s no trend in Texas gullywashers.
What’s vividly clear is the extreme vulnerability created by the continuing development pulse in some of the state’s most hazardous places — including Hays County, in the heart of an area that weather and water agencies long ago dubbed “Flash Flood Alley.” (Here’s a great interactive explainer.)
Hays County, Texas, one of the areas hardest hit by flooding on Memorial Day weekend, has seen extraordinary population growth in recent decades. Data are from Census.gov.
Hays County, Texas, one of the areas hardest hit by flooding on Memorial Day weekend, has seen extraordinary population growth in recent decades. Data are from Census.gov.Credit
The region’s population and building booms are far outpacing efforts to reduce exposure to flood dangers, resulting in long-predicted scenarios playing out at high cost in lives and money.
“The main challenge to rational planning for flood risk in the country is that private property rights trump even modest limitations on floodplain development,” said Nicholas Pinter, an expert on floods, people and politics at Southern Illinois University, in an email today. “And that sentiment runs deep in Texas. The result is unchecked construction on flood-prone land, up to the present day and in some places even accelerating.”
It’s worth noting that a similar pattern, although with a different mix of drivers, can be seen far from the strip malls and condos around Austin. In some of the world’s poorest places, rapid population growth and flimsy housing in zones of profound “natural” hazard have created huge vulnerability (the latest case in point is, of course, Nepal).
In Texas, there’s a “too little, too late” feel to the steps that have gotten under way — including a variety of United States Army Corps of Engineers studies of flood risk.
One such flood analysis, for the northern part of Hays County, begun in 2011 and is just now entering final review. The risk was laid out four years ago in an announcement of the study:
Hays County’s population has been increasing dramatically – the county’s population grew from 97,589 in 2000 to 157,107 in 2010, a 61% increase. Development has subsequently increased as well. This growth has the potential to place residents at a greater risk for human and economic losses from floods.
In a telephone interview, Randy Cephus, a public affairs official in the Corps’s Fort Worth district office, said this was a fast pace. “The Corps has gone through a transformation,” he said. “In the past, studies have taken 8 to 10 years to complete. We’re trying to undergo those within 3 years.”
It’s important to get these studies done, but I doubt they’ll have much impact as long as politicians and communities in the region stick with the go-go development mentality that has been so vividly on display.
I see little evidence that leaders in the region have paid attention to the vast volumes of information they already paid for. The websites of Texas agencies responsible for managing water and limiting disaster losses are already full of valuable information clearly laying out the deep hydrological vulnerability in the state.
Click here for a particularly relevant section of a voluminous and valuable report on hazard mitigation from the Guadalupe-Blanco River Authority, an agency responsible for managing water-related issues in part of the area devastated in recent days. It includes this sobering map showing that epic downpours, and flash floods, have occurred around the state:
A map in a 2005 flood safety report showing past extreme downpours in Texas, drawing on data from the United States Army Corps of Engineers.Credit Guadalupe-Blanco River Authority
In the meantime, most regional coverage of growth has centered on the economy, which is fine if it is meshed with environmental considerations and doesn’t lead to costly public bailouts when disaster strikes. (Google for
Here’s a KXAN web report from March on census data showing Austin’s growth lagging only Myrtle Beach in the Carolinas and a couple of retirement hubs in Florida.
Zoom in on San Marcos, Tex., home to thousands of Texas State University students and staff through this 2013 feature on the building spree there: “Apartments sprouting up throughout San Marcos.”
The town was hit hard over the weekend. To see what a combination of sprawl and extreme flooding looks like, a good place to start is the drone video posted on YouTube by Stephen Ramirez, a photographer from San Marcos with a background in environmental science. Here’s an image, isolated from the video, showing the new Woods of San Marcos apartment complex.
A new apartment complex in San Marcos, Tex., one of many fast-growing communities hit hard by flooding.Credit Stephen Ramirez/ Birdsiview.org
In an email exchange, Ramirez explained that the lack of resilience created in the region’s crowding flood zones has been accompanied by environmental impacts, as well:
There are a lot of citizens in the community who are extremely frustrated with the inappropriate locations of development within our watersheds. Recent and planned developments along the floodplain and riverfront of the San Marcos river, and the sensitive Edwards Aquifer recharge zone that feeds it, have been a heartbreaking loss for this community. We are sick of get-rich-quick developments that lack the foresight to maintain the quality of life and preserve our endangered natural resources.
There’s much more to write on the issues raised in Texas and so many other places where communities have yet to figure out a balanced relationship with environments, for the sake of both people and the planet. Stay tuned.
To close things out, here’s the promised deeper dive on flood and rainfall trends in the state in the context of global warming.
I queried several climatologists I know in Texas. Andrew Dessler at Texas A&M encouraged me to ask John W. Nielsen-Gammon, the state climatologist. He offered these thoughts and studies, which, in the aggregate, point to no robust trend either in extreme downpours or extreme stream flows:
I’ve analyzed long-term overall precipitation trends for 1895-2009. They’re positive [across most of the United States].
Groisman et al. [Changes in Intense Precipitation over the Central United States] found trends in extreme precipitation in the south-central United States.
William Asquith has analyzed long-term streamflow trends in Texas. They’re not significant.
Villarini and Smith looked at changes in extreme flows in 62 gauges with record lengths of at least 70 years, and found 2 with statistically significant increases and two with statistitcally significant decreases.
My comprehensive study of Texas rain events of 20+ inches from 1948-2002 found no overall change in frequency over the period.
There are plenty of people who are trying to center the Texas flooding discussion on climate change.
There are plenty of reasons to curb greenhouse gas emissions and advance clean-energy technology.
But it’d be best if those issues did not obscure the glaring opportunities communities have to limit losses from worst-case weather, whatever mix of factors is involved.
Updates, 10:00 p.m. |
Katharine Hayhoe, a climate scientist at Texas Tech University (and a lead author of the 2014 National Climate Assessment) sent this reaction:
One of the most important reasons we care about climate change is because it exacerbates the risks we already face today. Texas is home to many of the fastest growing metro areas in the U.S. This rapid urbanization and development changes the face of the land, increasing flood risk at a time when, at least for the eastern half of the state, the risk of heavy downpours is also on the rise.
Kevin Simmons, an Austin College economist best known on Dot Earth for his valuable studies of tornado impacts and efforts to reduce them, weighed in not as an expert on floods, but as a lifelong Texan living in flood country outside of Dallas:
This is not my research area so my comments are anecdotal. But I have lived in Texas all my life and have witnessed this over and over. First, Texas is absolutely pro-development and this can create both short-term issues and long-term ones as well. In the short term, the developer pushes the limit in terms of building in flood plains and there is often little resistance. But in the longer term, even if the developer stayed away from existing flood plains, future development changes the flood patterns. So a home that was not in danger 20 years ago is now in danger because a shopping center has paved over 40 acres of land that once absorbed runoff. That runoff is now headed downstream.
Second, flood protection is often to protect business interests and not residential. Case in point, the levees on the Trinity River than runs just south of downtown Dallas. The levees begin a few miles west of downtown and end just east. The levees were built after a flood on the Trinity that inundated downtown. A current example of lack of foresight on the part of planners is the dream of some civic leaders to build a toll road in the flood basin of the Trinity.
Third, Nicholas [Pinter, cited in post above] is right that we flood more than we want to admit. We live north of Dallas-Fort Worth, close to Lake Texoma. When the dam was built, it was estimated that water would only go over the spillway once in 100 years. Well, it has done that 4 times in the last 58, twice since we’ve lived here — 2007 and now this year.
Developers like to “move some dirt’ in the Texas vernacular. They have a great deal of power. Dallas-Fort Worth is exploding in population right now. Every new subdivision or shopping center has an impact on the safety of people and property downstream. We should learn from each flooding event but I’m not sure that we do.didn’t exist just a few decades earlier.