Models show 'massive devastation' in Houston
Damages could cost up to $50 billion -- 10 times Allison's cost
By ERIC BERGER
Copyright 2005 Houston Chronicle
Houston CronicleHouston's perfect storm would feed on late summer's warm waters as it barreled northward across the Gulf of Mexico, slamming into the coast near Freeport.
A landfall here would allow its powerful upper-right quadrant, where the waves move in the same direction as the storm, to overflow Galveston Bay. Within an hour or two, a storm surge, topping out at 20 feet or more, would flood the homes of 600,000 people in Harris County. The surge also would block the natural drainage of flooded inland bayous and streams for a day or more.
Coastal residents who ignored warnings to flee would have no hope of escape as waters swelled and winds roiled around their homes. Very likely, hundreds, perhaps even thousands, would die.
Meanwhile, as the storm moved over western Harris County, its most dangerous winds, well in excess of 120 mph even inland, would lash the Interstate 45 corridor, including Clear Lake, the Texas Medical Center and downtown.
Many older buildings could not withstand such winds.
Anything not tied down, from trees to mobile homes to light poles, would become missiles, surreally tumbling and flying through the air, flattening small houses, shattering skyscraper windows and puncturing roofs.
"Unfortunately, we're looking at massive devastation," said Roy Dodson, president of the engineering firm Dodson & Associates, which Harris County asked to model realistic "worst-case scenarios" for a major hurricane hitting the area.
Dodson's firm modeled more than 100 storms of varying power, speed and landfall. It concluded that a large Category 4 or Category 5 -- a storm only moderately larger than the four that struck Florida last summer -- would cause as much as $40 billion to $50 billion in damage. That's 10 times the cost of Tropical Storm Allison and approximately the city of Houston's entire budget for the next 15 years.
And this wasn't an academic exercise. Of the 17 Category 4 and Category 5 storms that have struck the United States since 1900, three, all Category 4 storms, have hit the Greater Houston area -- unnamed storms in 1900 and 1915 and Carla in 1961.
Coastal development
With considerable coastal development since then and lower elevations because of groundwater pumping, no one knows what will happen when a major storm hits. But what's clear is that models of a hurricane's three modes of destruction -- winds, storm surge and inland flooding from heavy rainfall -- offer little comfort.
With sustained winds between 131 mph and 155 mph, the power of a Category 4 storm exceeds that of most building codes.
Houston's commercial building rules call for structures to withstand three-second bursts of at least 110 mph, said Dennis Wittry, managing director of Houston Structural Operations at Walter P. Moore, an engineering firm.
Newer skyscrapers, including many built during Houston's downtown boom in the '80s, were modeled in wind tunnels to determine their performance in extreme weather events. Most should survive the storm, Wittry said. And the downtown window loss like that experienced during Hurricane Alicia, a Category 3 storm that struck in 1983, actually could be less in a bigger storm.
That's because roofs that were then anchored by gravel -- which become bullets in high winds -- are now held down by specialized concrete that should not blow off, Wittry said.
Residential homes, built with less exacting standards and lesser materials, would fare worse.
"You'll definitely see more significant damage in residential construction," he said. "Lower-end homes, or some homes in older areas, would probably be completely destroyed."
Tie-downs, a structural device that prevents wind blowing over a structure, creating a vortex and sucking off the roof, have been mandatory only since the late 1980s, Wittry said.
Various studies of a large storm hitting the Houston area have estimated that 100,000 to 125,000 homes would be destroyed.
20-foot wall of water
More devastation would be caused by winds blowing over the Gulf of Mexico and pushing surface water inland -- creating up to a 20-foot storm surge. Such a wall of water would swamp most development near Galveston Bay, including Texas City, Kemah and Johnson Space Center. Varying levels of water would flood much of the area between Sam Houston Parkway and the bay.
On Galveston Island, the seawall could hold back much of the storm surge, but at some point the water would creep onto the island from the bay side. The island's highest point is just 22 feet above sea level.
Much like a river becomes deeper and more turbulent when it narrows, a storm surge also can increase in height and intensity when its source of water narrows. Dodson said this has profound implications for the Port of Houston. Some models ended with a 30-foot wall of water in the Ship Channel near the port's turning basin, he said. "It would be huge," he said. "It could overwhelm chemical storage facilities, water treatment plants and other sensitive areas."
The port's severe-weather plan calls for most cargo ships to exit the facility and weather the storm at sea in preparation for the possibility of flooded buildings.
waves expert at Texas A&M University at Galveston, Vijay Panchang, said he and colleagues were surprised when they observed wave data associated with Hurricane Ivan shortly before it slammed into Alabama last September.
A wave-measuring buoy about 60 miles south of Dauphin Island, before it snapped, registered an average wave height of about 50 feet, Panchang said. That means the biggest waves were a staggering 100 feet tall. Such wave heights, according to his modeling, should only occur every 300 years or so.
Either Ivan's waves were a freak event, or hurricane forecasters may need to adjust their wave expectations for large storms in the warm Gulf waters.
"This is from a storm that hit only a few hundred miles to the east of us," he said. "There's nothing to say that another storm won't create really big waves for us."
These large waves caused by Ivan may have been as responsible, if not more so, than the storm surge for severely damaging the I-10 bridge bear Pensacola, Fla., Panchang said.
Surprises after landfall
Engineers and forecasters say the most unpredictable element of a storm comes after landfall, when it either dumps rain and floods creeks and bayous or moves quickly enough that relatively little rain falls.
Tropical Storm Allison probably isn't a good model for what to expect. The system was so poorly organized and slow moving that some hurricane forecasters say it wasn't a tropical storm. In some areas of the city, enough rain fell to classify Allison as a 10,000-year rainfall event. Still, because a large hurricane's storm surge likely would block the flow of bayou waters into Galveston Bay, any significant rainfall could back up into inland streets and homes quickly, Dodson said.
The last major hurricane most Houston residents remember was Alicia, which made landfall on the west end of Galveston Island in August 1983.
Unfortunately, planners say, as devastating as that storm was, it's a poor predictor of what to expect from a larger, Category 4 or bigger storm.
Alicia's highest sustained winds on land were measured at 96 mph. Most of the Greater Houston area received just 5 inches of rain. Storm surges across much of the area were less than 10 feet, although Seabrook measured 12 feet.
The storm spawned 23 tornadoes, killed 21 people and destroyed 2,300 homes.
"Alicia was a marginal Category 3," Dodson said. "Its rainfall doesn't come close to this area's top 20 historical floods.
"I guess what I'm saying is that I hope people don't ignore evacuation warnings because they remember that things weren't apocalyptic during Alicia."
Let's not make the same mistakes as were made with Katrina. Rita is a killer and people in Houston and Galveston, Texas City, Freeport, Bay City and the surrounding areas need to evacuate.
Last edited by Nbadan; 09-22-2005 at 02:42 AM.
Free Housing!!
http://www.hurricanehousing.org/resu...05&distance=50
For anyone who is looking for a place to evacuate out of Houston or the Coastal region. It's sponsored by moveon.org so you'll probably get to smoke and drink more than with a right-winger, no promises though ..... but seriously, we all know Rita is a monster. Please pass this link along to anyone in serious need.
How come the basement is not an option anymore?
i agree with dan...will wonders never cease...good post dan.
Do homes even come with basements these days?
There's a mandatory evacuation in effect. All major roads out of Houston heading west and north are being made one way.
Traffic lanes jammed out of Houston, cars breaking down and running out of gas. Josh Marshall thinks we could be another day away from another national disgrace...
Talking Points MemoSeptember 22, 2005 -- 12:53 PM EDT
TPM Reader LH reports in ...
A brief note on the evacutation of the Houston area. Galveston and all the coast was successfully evacuated but Wednesday night there occured throughout Houston a simultaneous mass (hysterical) evacuation. All the freeways and highways leaving Houston are at a dead standstill as of 11am Thursday. People have been in their vehicles as long as 12 hours without traveling more than 40 miles. Now they are running out of gas and there will soon be another chaotic storm evacuation situation. The local government and the mayor of Houston don't seem to realize that cars need gas and folks need facilities. The city has waited too long to open all freeway lanes to outbound traffic. The truth is, the feds, state, and locals do not know how to evacuate a major metropolitan area. Another catastrophe is only a day away.
Let's hope not.
-- Josh Marshall
Did anyone see the UT computer models of what will happen to Galveston if they get a direct hit. It was as mesmerizing as watching that JetBlue airliner land.
Houston chronicle Hurricane blog
Scary traffic stories so far. Sitting in traffic for many hours, little or no gas or bottled water left, poor people without buses. Sounds depressingly familiar.
I am in Waco today and have run into some folks evacuating. The stories are true. One woman's nephew left Baytown yesterday at 11:00am and got to Waco at 4:00am.
Funny, I saw on GMA this morning video footage of Galveston using thier school buses to drive people out of Galvestion. And IH10 and IH45 are now one way from Seguin and Buffalo, respectively. So the traffic is moving a little more smoothly, but still really slow I'm Sure. Gas trucks are also being deployed.
WOAI Reporting
I guess we see just how prepared state and local officials should be!! What a novel thought: using school buses to evacuate people!!Governor Rick Perry says fuel trucks are being dispatched along Texas evacuation routes to help motorists who are fleeing Hurricane Rita.
Perry today announced the fuel will be available, such as along Interstate 45, where some drivers have run out of gas due to the slow traffic flow.
The Texas Department of Transportation’s (TxDOT) San Antonio and Yoakum Districts are working in conjunction with Alexander Oil to provide fuel to motorists traveling down IH 10. TxDOT has stationed 14 trucks along IH 10, which will provide stranded motorists with 5 gallons of fuel, enabling them to reach Seguin. Motorists will be able to refuel in town. The Texas Department of Transportation will be providing this service until it is no longer required.
Perry also spoke to President Bush today and asked that ten-thousand federal troops be pre-positioned to help Texas before and after Rita makes landfall.
That's in addition to the five-thousand Texas national guard troops that the governor has called to duty.
Also, Texas authorities have begun airlifting special needs and other people from the Beaumont and Houston areas -- about nine-thousand folks.
Homeland security officials say those evacuees will be transported to San Antonio, Amarillo, El Paso, Dallas, Fort Worth and Lubbock.
Moving people in buses from Galveston to Houston is hardly a rescue plan, but whatever floats your boat, oh and by the way, if Louisiana had the resources that Tx does I'm sure Governor Blanco would have done anything that was necessary. Neither the City of NO, nor the State of Louisiana own school buses. Remember that New Orleans evacuated 80% of its residents in 2 days with minimal federal assistance, hummm, I wonder how many Houstoners have made it out of town so far?
Last edited by Nbadan; 09-22-2005 at 01:27 PM.
You mean the 180 buses in NO that were under water because the mayor didn't use them?
Oh, so now there were no school buses in NO.
The City/State did not own those buses, they are privately owned, but that's something Sean Hannity always forgets to mention.
Meanwhile, the evacuation of Houston seems to be going just maaaarrvelooussss..check out this Houston highway cam...
This is just a few minutes old.
Houston TransGuide
Doesn't matter. The buses were at the city and state's disposal had they actually prepared.
Adjust your tinfoil hat, kiddo.
The City/State did not own those buses, they are privately owned, but that's something Sean Hannity always forgets to mention.
Meanwhile, the evacuation of Houston seems to be going just maaaarrvelooussss..check out this Houston highway cam...
This is just a few minutes old.
Houston TransGuide
What should Houston have done differently?
Used the school buses!
We've gone through this before, but if you care to rehash old arguments, do so at your own peril. Where were these school buses, with no air conditioning, no bathrooms, and no plans for gas beyond what was already in the gas tanks going to go? I heard a caller ask Jeff Bolton that question on OAI one day, and the only answer he had was North...North where? There was no regionally coordinated evacuation plan for New Orleans, as unfortunately, there seems to be no Federally coordinated evacuation plan for Houston.
Presumably they would have ended up someplace better than 12 feet below sea level. Duh.
Well, they could piss in it, anyway.
Yeah. like along the stretch of I-10 that ended up in the Gulf.
I'm sure you guys have covered this before in the multiple blame Bush threads, but where exactly does to sy it is the federal governments job to have an evacuation plan for one particular city. I would be under the assumption that that is the city and state gorvernments job. I know go there at my own peril.
By that time the buses were also under water. If the buses had been used, they would have been out of NO by the time the hurricane hit. BTW, Dan you do know there are other roads besides I-10 out of NO, right?Yeah. like along the stretch of I-10 that ended up in the Gulf.
Yeah. like along the stretch of I-10 that ended up in the Gulf.
Please. If NO had evacuated ahead of the storm like Galveston did then that wouldn't be a problem.
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