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Scientists Strive for Way to Issue Earlier Tornado Warnings

June 1, 2011 at 12:00 AM EDT
This spring has been one of the deadliest tornado seasons ever, prompting questions about just how well scientists can anticipate and warn people of storms about to strike. Tom Bearden reports on researchers who are trying to improve warning systems in the hopes of saving more lives.


JIM LEHRER: This spring has been one of the most deadly tornado seasons ever. Just today, much of the East Coast, from Pennsylvania to Maine, has been under a tornado watch.

This has raised questions about how well scientists can anticipate and warn of the storms to come.

NewsHour correspondent Tom Bearden reports on efforts to improve the record.

TOM BEARDEN: The May 22 tornado that flattened a large part of Joplin, Mo., killed well over 100 people. It was classified EF-5, the most damaging storm on the scale. Less than a month earlier, an EF-4 twister roared through Tuscaloosa, Ala. It and other tornadoes that day killed some 300 people.

People in both towns were warned. In fact, Joplin got 20 minutes of advance notice, far more than the average of about 13 minutes. Could more timely and more accurate warnings have saved lives?

Josh Wurman has been chasing tornadoes for 15 years, but he’s quick to say science still has much to learn.

JOSH WURMAN, Center for Severe Weather Research: The big missing pieces are the real details of exactly how the tornadoes form, and how to distinguish between the thunderstorms that are going to make tornadoes and the ones that aren’t.

Most of them don’t. Most of these threatening rotating thunderstorms don’t make tornadoes. But a few do. And in order to predict better when the tornadoes are going to form, we need to be able to distinguish between the ones that do and the ones that don’t.

TOM BEARDEN: Wurman is the president of the Center for Severe Weather Research headquartered in Boulder, Colo. Six years ago, I was with his team as we raced across the back roads of Kansas and Oklahoma trying to position truck-mounted radars to peer into the mystery of how nature’s most violent storms are born.

In the years that followed, they have developed some new tools.

JOSH WURMAN: In order to see in that blind area right at the ground, we deploy these tornado pods. And we have 18 of these. And when the tornado is moving, generally east, we drop a whole row of these, like a picket fence, in front of the tornado, and we hope that it runs over one or several of these.

And we measure wind. We measure wind in a different way. We measure temperature, relative humidity, and then we record all this data inside here. And this is tougher than an aircraft black box. So, even if these instruments get destroyed, the data, which is what is really important, survives inside this, and we can pick up the box and download it to a computer.

TOM BEARDEN: Tornado research got a big boost over the last two spring tornado seasons. Wurman was one of the participants in a project called VORTEX2, the largest effort ever made to understand tornadoes. It involved more than 100 scientists and 50 chase vehicles.

JOSH WURMAN: Scientists from VORTEX2 are working on dozens of terabytes of data that we collected from mobile radars like what’s behind me, from instrumented vehicles, weather balloons. We’re trying to synthesize all that into a better picture of how tornadoes form.

I think, within one, two or three years, we are going to make those breakthroughs.

TOM BEARDEN: The goal is to increase warning times to perhaps 30 minutes.

JOSH WURMAN: If people had 30 minutes to get to safety, maybe more of them could get out of their houses, get out of their interior rooms, and really get to a tough community shelter, so they could survive one of these EF-5 tornadoes, which just wipes out all the rooms in a house. It doesn’t matter if you’re in an interior room or not.

TOM BEARDEN: Other scientists are building on the evolving knowledge of how and why tornadoes form to create new technological approaches to improving warning times for people in harm’s way.

Scientists from Colorado State University and the universities of Massachusetts, Oklahoma, and Puerto Rico are working to develop networks of small radars like this one under a 10-year grant from the National Science Foundation.

When networked together, the dishes can provide a lot more information to weather forecasters than the existing large weather radar systems. They have been testing a network of four of these radars in Oklahoma for the last four years.

Dr. V. Chandrasekar is the research director.

DR. V. CHANDRASEKAR, Colorado State University: In the couple of examples we have had where the tornado has actually come into our network, the forecasters that use this data, with a lot of training, they have felt that they were able to get somewhere between three to five additional minutes of lead time in predicting tornadoes and warning — warning for tornadoes.

TOM BEARDEN: Francesc Junyent is the project’s chief engineer. He says the system operates pretty much without human supervision.

FRANCESC JUNYENT, Colorado State University: As soon as something enters the domain, the system will focus on it and will keep track of it, as well as any other thing else that pops in that domain.

TOM BEARDEN: And he says it provides more information much more quickly.

FRANCESC JUNYENT: It’s faster in the sense that the radars will reposition themselves at a faster rate.

I mean, just from a very intuitive point of view, right, moving something big is a lot harder than moving something small. So, these radars will be much more agile in how they scan.

TOM BEARDEN: They’re about to start building a new network in Dallas that will be twice as large as their test system.

DR. V. CHANDRASEKAR: We hope to give, in addition to tornado warnings and watches, very effective street flood warnings, to prevent street flooding and then cars getting stuck in street floods and so on.

So, some operation like this, you could deploy in a metropolitan environment as a network, so it’s like — it just provides a protective shield for that whole metro environment.

TOM BEARDEN: This spring’s deadly outbreak has people asking whether tornadoes are becoming more frequent.

Josh Wurman says the country is on a record pace, but not that much above the record.

JOSH WURMAN: It’s probably just really bad luck. The tornadoes this year have gone through cities. We had one go through Tuscaloosa. We had one go through Joplin. And when a tornado goes right through a city, it can destroy thousands and thousands of structures, and, as we see, 100 people or even more can die.

TOM BEARDEN: While science is working hard to make earlier warnings possible, not much will be accomplished if people ignore them.

Another goal is to reduce the error rate for tornado warnings, which now stands at 70 percent. Research shows that people tend to ignore warnings if they know most of them turn out to be false.

JIM LEHRER: As we reported earlier, the total number of dead in the Joplin tornado was confirmed today at 134.