Revisited--Exit This Way: Research informing upgrades in hurricane evacuation planning.

As the 2024 hurricane season approaches again, climate experts across the United States are predicting an especially active season, driven largely by higher-than-average sea surface temperatures. This makes ever more important the research and planning that begins long before extreme weather strikes, and continues long after the storm has passed.

Transcript

Bernie Fette: 0:14

Hey everyone. Welcome to Thinking Transportation -- conversations about how we get ourselves and the stuff we need from one place to another. I'm Bernie Fette with the Texas A&M Transportation Institute. Hurricane season is upon us once again, and climate experts across the U.S. are predicting an especially active period from June through November, driven largely by higher-than-average sea surface temperatures. With more storms than ever expected to reach hurricane intensity, the need for careful and effective planning for storm response has never been more urgent. With that in mind, we are rebroadcasting a previous episode on this topic, featuring David Bierling, a research scientist at TTI and an expert in the field of mass evacuations of areas affected by weather disasters. Thank you for joining us, David.

David Bierling: 1:12

Thank you for having me, Bernie.

Bernie Fette: 1:14

Before we consider the hurricane season that just started and the work that you're doing, let's talk a little bit about hurricane history, if we could, particularly in Texas. Can you give us a quick review?

David Bierling: 1:28

You know, hurricane season just started here on June 1, and it runs up into November. But that being said, there's definitely peaks in the season about a quarter of the tropical cyclones that affect Texas in some way or another. And this is not necessarily even getting to a hurricane level storm. We can have a tropical storm like Allison that has a major impact. Of course, a tropical storm Allison came in early June, 2001, dropped a lot of rain in southeast Texas and really screwed things up. So we've got about a quarter of the storms that impact Texas in July and June, and about another 60 percent impact Texas in August and September with most of that impact coming in September.

Bernie Fette: 2:11

And that's a pattern that typically follows from year to year or season to season.

David Bierling: 2:15

The short answer, Bernie, is yes, that's a typical pattern that tends to hold out. Hurricane season runs from June through November.

Bernie Fette: 2:22

It's helpful for us to understand that pattern. And it sounds like that that pattern typically, or generally speaking, follows from year to year , from season to season . Considering that history again, are there any ways that tropical storms, hurricanes, and other storms have changed over that time?

David Bierling: 2:43

Well, climate researchers are seeing evidence that storms seem to be intensifying over time. So if you look at some of the research that the folks at NOAA put out and other researchers, they're saying that given changes in climate, we can expect to see more intense tropical cyclones.

Bernie Fette: 3:04

Okay. And that quick review brings us up to now, and most of the predictions that people can find online about the 2022 tropical storm season say that it's going to be a more active than usual few months, more storms that will be intense enough to earn a name and of those more that will reach hurricane intensity. Right? So to help agencies prepare and help people prepare for that emerging reality. You and your colleagues have been pretty busy with your research. Please tell us about the work that you're doing.

David Bierling: 3:41

Sure, yeah. A , a lot of the work we've been doing is focusing on updating the plans for hurricane evacuation zones. Of course, TTI does a lot of research on different aspects of climate and resiliency. And those tie in with the tropical cyclones as well. Though we've got folks that are studying infrastructure vulnerability. When a roadway is damaged because of a storm event, how can we diagnose what that is? How can we rehabilitate it better? How can we use intelligent transportation systems to understand where roadways are gonna flood? So we've got a lot of things going on here at the agency. What we do is we take the latest information from NOAA and the National Hurricane Center about, for example, storm surge, how high might the water get? And we overlay that with other information to help communities better understand where the hazards are. And then we work with them to update the evacuation zones that they can use to plan and implement a response for a storm that comes in. And then we look at more intense storms that might come in and look at the storm surge, where it's going to impact who's there, what is the infrastructure. And we , when we're working with communities to help update these evacuation zones, we're going to now is identifying recognizable geographic boundaries. And often those are roads, right? Major roads in an area 'cause people are gonna know those, they travel those every day so they can recognize that. And that's kind of a direction we've moved towards rather than if you've seen maybe some of the old evacuation zones where it's kind of got like this curvy area, you know, it's nice and smoothed out and it might follow exactly the topography of the forecasted surge impact, but that's not as useful for decision making . We need to give folks a recognizable geographic landmark that they can understand. Our work has been in partnership between TTI and Texas A&M University's , uh, hazard Reduction and Recovery Center. And we've been working on projects funded through Army Corps of Engineers and FEMA in partnership with the state division of emergency management, other state agencies, and most importantly with local communities and jurisdictions. And that's been to understand what are the impacts due to hurricanes, particularly storm surge. If you look in terms of life risk and life safety is always a priority in terms of life risk. About half of the fatalities from tropical cyclones tends to come from storm surge with the others, from other related impacts, drowning and those sorts of things.

Bernie Fette: 6:27

And , and whenever you mention storm surge, just so we can be sure everyone understands the storm surge, is the water as opposed to the impact that comes from the wind, is that oversimplifying?

David Bierling: 6:40

That's it's close. Okay . So storm surge, if I think about that, I have a storm, a cyclone, and it's rotating over water. And as a result of the winds and the rotation, it builds up a wall of water. And typically that wall of water is greatest on the northeast quadrant because of the way the rotation is of the storm. Right. Okay . Right. And it's not the , the , the level of water. So the storm is building up this water and it comes in and it hits land, and as it hits land, that wall of water comes up and it envelops the coastal areas, the lower coastal areas that are adjacent to the coast. Of course then the storm might also drop precipitation. Right. And so we had this, for example, it Harvey's a recent example that comes to mind. So it hit the first landfall in Texas, hit as a hurricane, a category four hurricane, went back over the water, moved up the coast a little bit, came in as a tropical storm and dropped lots and lots and lots of rain. So that was a precipitation event. Both of them are water. One is where I'm driving this wall of water from the sea surface or the gulf surface here in Texas. Another one is I'm dropping a lot of precipitation. It collects and has to go somewhere. And if there's too much precipitation or if I'm getting precipitation, that comes from a place that's upstream and flows downstream, and then the river comes out of its banks . Those are two types of water-driven events that can also affect, but there's certainly other impacts. Wind, hurricanes can also spawn tornadoes. We have impacts called na-tec disasters where I have a natural disaster, like a hurricane that comes in. And here in Texas we've got lots of energy and petrochemical infrastructure. So it comes in and then it impacts a facility of some sort. And now we've got a technological disaster. So those are called na- tec events. So it's not necessarily that a tropical cyclone only causes storm surge events, even though that's where a lot of our work has been on these projects, there's a great variety of hazards that can happen from them.

Bernie Fette: 8:47

So tell us a little bit more about the focus areas that you're working on in terms of , again , this all kind of revolves around the notion of evacuation, correct? Mm-Hmm. <affirmative> .

David Bierling: 8:59

Yeah. Well, as storms and storm forecasting has changed over time, NOAA and its other partners have been able to update their storm surge forecasts. So they do modeling where they look at what is the maximum level that they expect for water to get based on a storm. And it's important to recognize here that just because a storm has a higher category of wind speed doesn't mean necessarily that's gonna have a greater level of surge than a lower category storm. Ike is a good example. Katrina's another good example where you've got a storm out there in the Gulf and it's a big, big storm, builds up a big amount of surge. You know, you've got this big wall of water that's sloshing out there in the Gulf, and it comes in and it drops down in intensity, the wind speed drops, but it's still got this big wall of water. There's a lot of momentum in there. And so just because a storm's a lower category in terms of wind speed doesn't necessarily mean that the storm surge effect is reduced as well.

Bernie Fette: 10:08

So does that then mean that a lower category number storm could produce more damage, more mayhem than a higher numbered category storm? Let's say, just for conversation, it's possible that a category three hurricane could be more destructive than a category five, depending on other circumstances like the degree of storm surge, et cetera.

David Bierling: 10:36

Yeah there's not a direct relationship. A lot of that depends on the history of the storm. What did it do before it got here? How long did it have to build up? What does that history of the storm that affects it? So just because it makes landfall at a lower category doesn't mean right that it's lost that intensity that it might have had before. Then I might also have a very small storm that has a very high intensity around the , uh, eye of the hurricane, for example, but it might not be very large geographically. Okay . It might be relatively compact. And then if I compare that to, for example, a category of wind speed lower, but it's much bigger now, I'm moving a lot more water, I've got a lot more energy in there, even though it's wind speed.

Bernie Fette: 11:20

Right. And location you mentioned could be, again, a lower category storm striking one area of the coast producing more damage than a higher category storm that perhaps made landfall in an area without as much petrochemical activity, refineries and population, right?

David Bierling: 11:41

Yeah, sure. And you know, talking about category, that that's actually an area that forecaster storm surge modelers, emergency managers are trying to get a little bit away of thinking about these storms only in terms of categories, right? And so that's why when we've used the most updated information available through NOAA and National Hurricane Center, they're looking at all sorts of different scenarios about if I have a storm that comes in from the south or from the southeast, you know, all that direction of how it impacts the coast, the topography of the coast is a big factor. You know, a place that's flat for a long, long, long way, water can go a lot more distance over there. If I've got this storm surge that's coming in, yeah. Then if I have something that's, for example, a big change in the topography right near the coast so that we've got a big change in elevation, I've got some sort of protection there. Think about manmade protection on the Galveston sea wall is a good example. So the water just, it can't go inland as far. And so topography plays a factor there, too.

Bernie Fette: 12:42

One of the things that I noticed in your research and that I wonder about is how demographics figures into the work that you've been doing and into the considerations that local communities and agencies have to take into account.

David Bierling: 13:01

Yeah. So we're pulling together a lot of information from a lot of different places, and we're consolidating that into a resource that we put together under our projects that we're calling the hurricane evacuation study atlas. And these atlases, they're available to the public, they're available to local agencies. They are a data and information resource that local agencies can use to understand where are their risks, who's in those locations, and what are their vulnerabilities. So for example, I might have a neighborhood or an area of my community that has a greater number of folks that have vehicle limitations, they don't have a car, or I might have folks there that are elderly, they might have medical concerns, I might have folks there that have language barrier issues. How do we get communications out to them? How do we get notifications out to them? And so when we take that information about where our impacts, who is there, we can start to look at what might my demands be for an evacuation or if not an evacuation, what are my community needs going to be when we're trying to get things back up and running? We've also included the information there from workforce. Where are people working at? Where are the workers living? One of the main drivers of a community's recovery after a major storm or a major disaster is getting that local economy back running. People need resources, folks need food, they also need jobs, they need income. They're really important. So we need to be thinking about in addition to just how do I implement the evacuation? How do I get things running again, once we're starting to recover. So we've put this information tool together, and by the way, we've put an address search tool in there that the public can use. And if they have a question about, okay, well I live in this location, in this address, they can look that up, what's my risk zone? Might my location be affected by storm surge? They can type in that address, turn on that storm surge layer, and find out what the storm surge impact for their community might be . Right now we've got the storm surge projections for the full Texas coast. So if someone is concerned about storm surge in their location farther up the coast, they can type in their address and see what the surge impacts are. We'd like to be able to update that information to include flood zones as well as wind for higher up the coast as well.

Bernie Fette: 15:26

You've covered a lot of territory here, David. What are the main two or three points that you hope that people would take away from our conversation today?

David Bierling: 15:34

Well, I think number one is there's lots of great resources out there that people can look at to take initial steps for their evacuation plans, follow the guidance given on Texas ready.gov , FEMA's preparedness website, National Hurricane Center, National Weather Service. There's very good guidance out there on how to be prepared. In addition, they need to think about their own situation, their own family, their own friends, their own community. So if I have to evacuate, where am I gonna stay? This is a big one. What am I gonna take with me? What do I need to do to get my home ready? What kind of resources do I have to get for that? Where am I gonna get those resources from? How many trips am I gonna be taking? Am I going to send a group ahead? And we have , uh, one or two people that stay behind to get ready and leave separately? And this is all part of preparedness. It's very important. Three, I need to understand that I might not be able to come back just because the storm's come and gone in two or three days, and if I've been able to get out and evacuate, I might not be able to get back right away. So I need to be prepared a little bit for the long haul. Recognize that local and state officials and federal officials are doing their best to get communities back online, but that doesn't necessarily mean that everybody's going to be able to just come back to their residence just because the storm's gone. These are things that we've looked at in some of our research and understanding these things helps us develop the models for assessing what are the evacuation times. That, in turn, helps provide local officials and state officials with information that they can hopefully use to make better evacuation decisions. If I have an area, let's say it's a major urbanized area and it's gonna take 72 hours, 96 hours to evacuate folks, and I get a rapid storm. Harvey spun up very fast, right? We remember 2017, Harvey wasn't expected to reach near the intensity that it did, but it spun up really fast. And when that happens, because of the time needed to implement things like contraflow, it's not like somebody just flips a switch and okay, well three hours we're doing contraflow, takes a lot longer to coordinate that. It's a major, major change in how transportation systems operate. And so I think that's a major consideration that people should have is that our local officials, elected officials, state officials, federal officials, they can't just make a decision on a dime and two hours later, okay, everything's all hunky dory . So people need to think about in advance, what am I going to need to do to help protect myself, help protect my family, my community, my friends, and how can we work together?

Bernie Fette: 18:13

Okay, last question. In 50 words or less, if you can, what motivates you to get up and come to work every day ?

David Bierling: 18:22

One, helping communities, working with great partners, working with great people, working on interesting puzzles.

Bernie Fette: 18:29

David Bierling, research scientist at TTI. This has been very enlightening, David, and very timely. Thanks for sharing your time and helping us understand this.

David Bierling: 18:39

Thank you, Bernie. It's been great to be here.

Bernie Fette: 18:42

Predictions for the 2024 tropical storm season call for hyperactive conditions. With the number of named storms and hurricanes well above the average over the past 30 years, we can expect tropical cyclones to be more numerous and more intense than ever before. Thanks to increasingly sophisticated modeling, hurricane forecasting has improved over time and along with it, so have the steps for evacuation and recovery -- altogether aimed at helping states and communities get back to the routines of life as quickly as possible after a tropical weather disaster. Thanks for listening. Please take just a minute to give us a review, subscribe and share this episode, and please join us next time for another conversation about getting ourselves and the stuff we need from point A to point B. Thinking Transportation is a production of the Texas A&M Transportation Institute, a member of the Texas A&M University system. The show is edited and produced by Chris Pourteau. I'm your writer and host , Bernie Fette. Thanks again for joining us. We'll see you next time .