It's hurricane season.
For residents of the Texas Gulf Coast, that means keeping the car gassed up, plywood in the garage for boarding up windows and the phone number of the relatives in Dallas on speed dial.
For Gordon Wells and his group at the Center for Space Research (CSR) at The University of Texas at Austin, hurricane season means making sure those residents — and officials responsible for public safetyknow what's coming, when it's coming and when they should leave.
Using satellite data, databases of infrastructure, population centers and natural features, and advanced computing, the CSR team generates computer models that show approaching storms, display graphics that help determine evacuation routes and who should leave when and graphics that help first responders know what they'll have to deal with.
The team is part of the Governor's Emergency Management Council, a group of state agencies and organizations that gather in the State Operations Center to organize the state's response to an impending disaster.
The team brings together resources of The University of Texas at Austin that can make an immediate difference in dealing with hurricanes and other disasters.
Hurricane season began June 1 and the forecast from the National Hurricane Center calls for an 80 percent chance that there will be 13 to 16 tropical storms, more than during an average season. Eight to 10 of those storms might reach hurricane strength and four to six of those might be major hurricanes where wind speeds exceed 130 mph.
Even before hurricanes Katrina and Rita in 2005, the computer models generated by the CSR team have been an essential part of preparing for tropical storms and dealing with their aftermaths.
The team's work begins before the start of the season with the development of three-dimensional models based on generic storms and databases. State and local officials can use the model results and visualizations to plan their responses.
“You're presenting model results in a dynamic context so that it's sort of like a film that covers several hours duration, where you can see each individual part of the event as it occurs — as the surge dome moves inland, as the wind fields sweep across and create damage,” Wells said.
Those viewing the images can see what areas would be underwater, what areas might be subject to damage and what routes are safest for evacuation.
“All of this is done as a preview to the hurricane season so that county judges, mayors and local emergency managers are able to organize some of their exercises and drills and have these immersive, or at least fairly detailed, re-creations to train with,” Wells said. “They can think about what areas they would need to evacuate and in what sequence to get people out of harm's way.”
Modeling on the fly
Those models are fine for practice and drills, but it is highly unlikely they would replicate the exact characteristics of a specific storm.
As hurricane season progresses, Wells and the team are watching the weather to model developing storms that could threaten Texas.
“As a depression forms over the Bahamas, as did Katrina and Rita, we're immediately on alert,” Wells said. “We'd be in that group of four or five agencies that are already advising and beginning to make preparations at a very early stage. This would be 120 hours out, or more in some cases.”
If the hurricane looks like it's going to enter the Gulf of Mexico, Wells' team moves to their positions in the operations center where it is among the first handful of agencies preparing for a storm that may hold consequences for Texas.
“We begin to follow a storm very closely and as it enters the Gulf we start to look at predictions of what that storm will be on landfall” he said, by checking models that reflect dynamic characteristics similar to those of the approaching storm.
As the storm gets closer to the Texas coast, the team begins to analyze the results of surge models based on current observations and forecasts of the storm's track and intensity.
A storm surge is the long run of water pushed forward by the force of the hurricane. The surge was higher than 25 feet in some areas during Hurricane Katrina. Most of the damage and the great majority of deaths caused by large hurricanes comes from the storm surge.
“We begin examining storm surge models based upon the forecast characteristics of the storm at landfall between hour-96 and hour-72 (before tropical storm-force winds strike the coast),” Wells said. “We then generate new results whenever the storm path or predicted intensity at landfall changes. The final model typically follows the last National Hurricane Center advisory before landfall.”
To update and run models and create visualizations of their results quickly and in detail, Wells relies on the Texas Advanced Computing Center (TACC) of The University of Texas at Austin.
“The graphics supercomputers at TACC, particularly Maverick, are important for rapid visualization of storm surge models using high-resolution data rendered with the maximum level of detail,” Wells said. “An operator can easily change the viewpoint on the area of interest and zoom into the model results to examine the interaction of storm surge with terrain features, vegetation and structures. The results are photorealistic and allow decision makers to gain an instant awareness of the magnitude of events.”
The visualization tools developed at TACC enable emergency managers and responders to view the areas they're interested in on handheld devices, according to Gregory S. Johnson, manager of the TACC Visualization and Data Analysis group.
“What that means for an emergency response team is that they can load a Web page, log into that machine (Maverick) and load the visualization of the region they're interested in, approximate the flood surge of the type they're interested in and they interact with that environment,” Johnson said. “They can fly around the scene and fly up and down the streets. It's actually pretty amazing.”
The forecast of the surge model is important because it can help get people out of the way.
“Populations living in a surge zone have to be allowed to evacuate first,” Wells said. “The inland folks may be in jeopardy but not in nearly the degree of jeopardy that people in the surge zone are.”
During Rita, which hit landfall near the Texas-Louisiana border, he said, people inland left voluntarily, creating massive traffic on the highways needed by the coastal evacuees.
“So folks from the coast were getting on the road and their path was blocked by people inland,” he said. “Too many tried to get on the road at the same time.”
Technology for special needs
Over the past two years, Dr. Linda Prosperie, a member of Wells' group, has developed databases for planning and tracking shelters for the general population and has assisted in the development of the “shelter hub” concept. Shelter hubs are centralized areas with existing infrastructure that can be used to provide mass care resources before and after the storm.
Much of her work is to help the state deal with special needs populations who need to be evacuated.
“One of the things learned during Katrina and Rita is that you'll spend probably half or more of your effort dealing with special needs individuals,” Wells said. “Their care requirements are just so extreme and getting resources to folks like that on the fly is a very difficult matter. Things like oxygen and pharmaceuticals and the resources for people who need dialysisyou've got lot of people on the move all at once under highly stressed conditions.”
Prosperie, a research associate at CSR, said she has worked with the Department of State Health Services, the Department of Aging and Disability Service and the Texas Health Care Association to build databases for medial special needs evacuees. The data includes nursing homes, assisted-living and intermediate-care facilities, hospitals and other state facilities.
Wells said lessons learned from the 2005 storms are being acted on to make working with special needs people more effective. One step is the development of a statewide database that identifies those living in the hurricane evacuation zone who will require assistance to evacuate. The Governor's Task Force on Evacuation, Transportation and Logistics made this recommendation last March.
Wells and others are working on a plan that would enable evacuation vehicles to be monitored at all times. Buses would be tracked with global positioning systems (GPS), and the drivers would receive special cell phones.
He said that such devices enables those in the operations center to keep track of where buses are. Last year, a bus convoy was headed for Texarkana — after finding several other shelter areas fullbefore it could be located and directed to a more appropriate site.
Constant communication allows the authorities to get emergency aid and supplies to a bus rather rather through local EMS vehicles, air ambulances and National Guard helicopters.
The next phase of evacuee tracking will put a radio frequency identification tag with each person, Wells said. As each person steps on the bus, he or she will be registered on a roster that automatically updates a statewide database.
“We want to design an end-to-end system where we've got the needs of individuals pre-identified through the registration process before an event and we can track him or her through each stage of evacuation and sheltering from start to finish,” he said. “That way we'll know who was left behind in the impact area and we'll have the absolute geographic location of their residence. And our search-and-rescue teams will have that inventory of sites on their GPS logs and can go in and check each one of those residences as they search through neighborhoods.”
Even before the storms makes landfall, first responders move in close to the action. They set up in places close to where the storm will hit, but safe enough so they won't be harmed by it.
“They'll be able to shelter themselves as the storm passes through, but they'll be able to make the most rapid entrance into the area that's impacted afterwards,” he said.
As an example, in the final hours before Hurricane Rita made landfall, the team prepared maps to show the responders when and where to re-enter the region after the worst of the storm has passed.
“Teams had digital copies and hard copies of that map out in the field and they could determine, using the local maps, exactly when they could attempt to get in and by what route and when storm winds had diminished to the point that they could get into the air,” he said. “You're going to have swift water rescues and other potential air rescues as soon as you can get a plane into an area that's below tropical storm-force wind.”
The group keeps working after the storm, using satellite information to track the impact of pollution and power outages. Following Hurricane Rita, the team used orbital radar imagery from the Canadian Radarsat satellite to detect oil slicks from sunken vessels and ruptured storage tanks in the Sabine Lake area near Port Arthur.
At the height of a storm, Wells' group works with many state agencies, voluntary organizations and private sector service providers.
“Including the federal agencies, I would say that 25 to 30 agencies would be requesting and receiving products of some kind during a major event,” he said.
If the forecasts are correct, there could be a major event this year. Get ready. It's hurricane season.
Source: Texas Advanced Computing Center