Chasing Storms for Science

A Techwise Conversation with a tornado-chasing, tornado-researching engineer

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Steven Cherry: Hi, this is Steven Cherry for IEEE Spectrum’s “Techwise Conversations.”

It’s been an especially harsh tornado season in the U.S. How harsh? As of June 8, tornadoes have killed 536 people, almost exactly the same number as were killed in the previous 10 years combined. Tornado season is coming to a close—just in time for the hurricane season. It’s hard for engineers not to wonder: Where’s technology when you need it? If we can’t invent new ways to ward off natural disasters, can’t we at least get perfect disaster warning systems?

Well, that kind of research would involve putting one’s scientific instruments—and oneself—directly in the path of tornadoes. My guest today, Tim Samaras, does just that. He’s the principal investigator for a research organization he founded called TWISTEX, which stands for Tactical Weather Instrumented Sampling in Tornadoes Experiment. In other words, Tim’s an engineer and a storm chaser. He joins us by cellphone from Denver, Colorado.

Tim, welcome to the podcast.

Tim Samaras: Good morning. It’s a pleasure to be here.

Steven Cherry: Tim, you and your crew have been out chasing tornadoes in the Great Plains, the Midwest, the Southeast since around mid-April. Without making light of the very large tragedies from Missouri to Mississippi this year, I gather from a storm-chasing point of view, it’s been a hell of a year.

Tim Samaras: Yeah, it has been a very scary year indeed. Unfortunately, for research it’s been a tough year as well. You’d think with all these tornadoes out here we’d have ample opportunity to study these, get up close and personal. Unfortunately, the opposite is correct. The super outbreak back in late April had tornadoes moving at 50 to 60 miles an hour, and trying to study a tornado, trying to set an instrument in the path of a tornado moving at that speed through the trees in Alabama, is almost impossible. Other days, similar results; we’ve had issues with roads and so forth, so we’ve had a mixed blessing. We’ve got an X-band Doppler radar board; we’ve managed to capture several tornadoes, basically birth to death with radar, but we have not been able to sample the tornado directly. We came very close. We’re hoping that towards the end of June we’ll be able to finish out with a bang—at least get one sample for the year.

Steven Cherry: So maybe you could just take us through the process. It starts, I guess, with a prediction and a report from NOAA [National Oceanic and Atmospheric Association], and you do your own, and then what happens?

Tim Samaras: Well, basically, how we start out—we look several days out in the computer forecast, and of course, we all know how dependable the computer forecasts are—it’s easy to validate by watching the evening news and when the weatherman says it’s going to snow and the next day it doesn’t snow. We have a similar problem; we as storm chasers and researchers have to decide whether the model data that we’re getting is accurate or not. And of course, we have to take a lot of it tongue in cheek; there’s several different model forecasts that are out there. But what we do is we try to assemble a forecast that we think is best for tornadoes several days out, and then of course we prepare our teams; I’ve got our TWISTEX team members from all over the country. And so we assemble basically underneath the developing storm. And we can pinpoint an area where we think tornadoes are happening down to a state, probably maybe three days out. And then the night before, we can probably nail it down to maybe a portion of that state. The morning of the big day, we could probably get it down to a couple of counties where we think tornadoes are going to be, and even then, that is not a sure bet. Tornado forecasting is extremely difficult; there’s a lot of processes in the atmosphere that we still don’t understand. That’s why we’re trying to go out and measure these things. Tornadoes are very fleeting, and once we do find a tornado, then of course we have to intercept it, get in its path, and deploy instruments which we have that measure all sorts of meteorological parameters—temperature, humidity, wind speed, direction, barometric pressure; we record the GPS location—all of these items are important for us to tell us why some thunderstorms create tornadoes and others don’t, and then also for us to understand how powerful the winds are of these tornadoes near the ground. The first 10 meters of the tornado is probably the least understood portion of the tornado because it’s so difficult to measure. Of course, I for some reason take on the most difficult portion of the tornado to measure, and that is the actual in situ measurement of the tornado core. For years, researchers have been gathering data by using mobile Doppler radar—basically X-band, K-band radar to basically look on the inside of tornadoes, measuring storm relative velocity and looking at the overall structure. They’ve been doing that for 10 years, and they have terabytes of data; they have very, very little data of what the ground interaction of the tornado near the surface. Of course, that’s where we all live, that’s where we have buildings, it’s where we are. And so that’s, unfortunately, probably the more important measurements to collect, to find out how powerful these tornadoes are near the surface. So kind of in a nutshell, we try to derive our best forecast and get out to the target. We kind of keep our fingers crossed, and we hope that a storm develops. And then once a storm develops, obviously, we hope that a tornado develops, and people sometimes take it the wrong way. Our ideal situation is for a strong tornado to develop out in the open country, in an open field where there’s no structures nearby. Obviously, we’re not the type that wish ill fate on anybody in terms of destruction; we would love to have a perfect scenario where a tornado develops in an open field where we go out and safely study it and no damage is done.

Steven Cherry: So how close to the core of the storm are you actually getting?

Tim Samaras: Well, that’s a popular question that people ask. We generally get in probably within a minute or two of the tornado passage. Last year we collected a measurement in the big Bowdle tornado on May 22nd just last year in South Dakota. We managed to escape out of there within 20 seconds of tornado passage, which is just a little too close for me.

Steven Cherry: That’s a little too close for anyone, I think. A minute sounds pretty close, actually.

Tim Samaras: Yeah, a minute is probably my threshold. That was kind of an unusual case of the tornado; there was very little road options for us to intercept. And we managed to find the one road and we managed to drop our big instrument and the tornado went right over the top of it. So we managed to collect a very good data set that day.

Steven Cherry: So how well are we predicting tornadoes right now, and has it gotten a lot better? And how good is it going to get soon?

Tim Samaras: Well, that’s a good question. You know, 20 years ago, maybe 25 years ago, tornado prediction was pretty tough, and the National Severe Storms Laboratory and the University of Oklahoma and several others developed the Doppler radar to use to actually detect rotation in a thunderstorm. And basically they look at the typical radar principles in detecting speed, and they found that they can actually see rotation. Ted Fujita actually identified this phenomenon in some of the earlier work, and so back in the late 70s, early 80s—actually spawned by the Wichita Falls, Texas, tornado that killed several people back in 1979, I believe—implemented the WSR-88D Doppler radar system that got installed across the country during the 80s. And this was a huge leap in terms of being able to provide advanced warnings. Currently, the advanced warnings now are about 10 to 15 minutes on average. Of course, a very strong system can be detected a half hour out. Unfortunately, there are systems that quickly spin up tornadoes that you may not have any warning on, so of course when you hear severe thunderstorms, you’re under tornado watch, so it’s always good to watch out for that type of phenomenon. What holds in the future—that’s a very difficult question. Scientists and engineers are trying to work at trying to understand tornadoes a lot more and trying to stretch that warning forecast out just a little bit longer by trying to better understand the environment that tornadoes are in. And there’s also some advancements in radar, and that’s going to improve, but that’s going to be a very slow process. You know, we’re probably right at the limitation of what we can do with the state of the art, so the gains that we’re going to get now are going to be pretty small compared to the gains that we got back in the 80s, if that makes any sense. And there’s going to be a long time coming. Supercell thunderstorms and tornadoes are sometimes very fleeting, and you run up against a physical process of being able to detect the rotation in the thunderstorm because the thunderstorm itself may not be rotating. In order to detect—a thunderstorm’s going to turn into a tornado before it even rotates; that’s about where you have to push it to get any better warning out of it, and that takes a lot of work, a lot of research, and to get to that point we are just not there yet.

Steven Cherry: So it’s going to take another real breakthrough like Doppler to make a big difference?

Tim Samaras: Yeah. I’m not sure how big of a breakthrough that is. My hunch is that it’s going to be in small steps; you know, we’ll be able to gain 5 percent, 10 percent, simply by knowing the environment that these storms are in and being able to warn the warning forecasters, saying, hey, here’s the immediate environment where these thunderstorms are going up; you stand a better possibility of the storm creating a tornado, and therefore you might be able to warn just a little bit early. It’s going to be a tough one. Again, to get another leap like what we had with the weather service radars currently in place, it’s going to take a little bit of work.

Steven Cherry: So you were a senior research engineer for a company called Applied Research Associates headquartered in Albuquerque, New Mexico. Tell us about that and how it fits with what you do now.

Tim Samaras: Well, that’s an interesting question. My background and the work that I do as a research engineer is we actually go out and study blast waves, and we measure explosive forces. We actually measure also shock-loading impacts on soldiers perhaps experiencing post-traumatic stress syndrome—probably triggered by being exposed to blast environments—and some of the brain injuries associated with that. We were trying to go out and measure how much blast force some of these soldiers were having. We actually designed and built small recorders that the soldier could wear so that they could measure these things in real time. And the goal there was to maybe have some sort of a system where the soldier could say, “Hey, I’ve just been exposed to XYZ blast. Better go get myself checked out.” So my background is instrumentation, high-speed photography, going out and trying to measure these processes. And of course, knowing that I love a good challenge, I decided to take my background and apply it to my favorite hobby, which is storm chasing, and so I’ve been able to combine the engineering research and my hobby into one, and everybody should be able to go out and do the things they love to do.

Steven Cherry: I totally agree. I’m sure you’re the sort of person who gets a certain enjoyment from risk taking the same way, I guess, rock climbers and sky divers do.  But unlike them, your risk taking is in service to humanity, and that’s got to be a pretty good feeling.

Tim Samaras: I don’t like taking risks; as I get older, I like my life a lot more. You know, I would just as soon be able to safely get into a place and safely get out without being right on the edge. Unfortunately, in this business, that’s certainly not the case.

Steven Cherry: Well, very good. Thanks for joining us today.

Tim Samaras: Well, you’re welcome. It’s a pleasure to be here.

Steven Cherry: We’ve been speaking with Tim Samaras about his life as a tornado-chasing, tornado-researching engineer. For IEEE Spectrum’s “Techwise Conversations,” I’m Steven Cherry.

This interview was recorded 14 June 2011.
Segment producer: Ariel Bleicher; audio engineer: Francesco Ferorelli
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