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Killer tornadoes, such as the deadly one that ripped through a popular campground on Virginia’s Eastern Shore back in July, are capricious assassins.

Meteorologists can predict when conditions are right for formation of a twister, but they can’t always pinpoint who is in gravest danger at what time. Sometimes there are false alarms. Sometimes warnings come too late.

The good news is that science is getting better at matching wits with these wicked winds.

“There’s a lot more that we know at this point than we don’t know,” said Paul Markowski, a professor of meteorology at Penn State, who visited NASA’s Langley Research Center Sept. 9 to give a talk called “How to Make a Tornado: Ideas Emerging from Decades of Theory, Simulation and Field Observations.” Markowski is one of the nation’s top tornado experts. His talk was part of the Colloquium lecture series.

“What we really have to do better on is reducing false alarms and in some cases increasing lead times,” he said in an interview before his talk. “But really, when you take a step back and look at how far we’ve come in the last three to four decades, I think it’s pretty impressive where we are today.”

Anatomy of a storm

Markowski’s explanation of how tornadoes are born covered everything from the theories of 19th century physicist Hermann von Helmholtz to observations by the ambitious VORTEX2 campaignfrom 2009 and 2010, described as the largest tornado research effort ever conducted.

He said the common notion of what makes a tornado — clashing masses of warm and cold air — is an oversimplification. In more precise terms, tornadoes emerge from what are called supercell thunderstorms. Those can combine warm, humid air near the ground with colder air at higher altitudes. Those conditions, along with several types of circular air patterns happening at the same time in different directions, can produce a thunderstorm that rotates.

“But not all rotating storms make tornadoes,” Markowski said. “Only some of them do.”

The final step in the tornado-creation process requires downward drafts of air at just the right temperatures. Those help to bring rotating air close to the ground where it can uproot trees, destroy dwellings and spread misery.

[For more on his description of how storms are formed, see this article by Markowski from the Weatherwise website.]

Markowski said that a big tornado year brings as many as 1,500 twisters to the United States. In 2011, almost 1,700 occurred. That might sound like a big number, but tornadoes rarely hit in exactly the same place. “It’s far less frequent than say an earthquake in California or a hurricane striking the North Carolina coast,” he said.

Chasing the wind

That fact made the VORTEX2 project all the more difficult. In the spring months of 2009 and 2010, a team of some 100 scientists, including Markowski, formed a mobile research team ready to race to wherever a tornado seemed likely. They comprised an armada of vehicles were outfitted with radars, probes and cameras.

Covering an area bounded by Canada and Mexico on the north and south and between the front range of the Rockies and the Mississippi River on the west and east, they gathered data on some two dozen tornadoes.

“By having everything on wheels and staying in a different city every night, basically going wherever the weather took us, we got the most bang for the buck, although the human experience was brutal,” he said. “Each vehicle in the project drove about 30,000 miles over a 12-week period.

“It was a good day when you got fast food. Most days it was truck stop food … It’s not as fun as it’s made out to be in many of the TV programs, I’ll leave it at that.”

Television took notice of VORTEX2. The Weather Channel followed the crew, giving the scientist an unexpected blast of celebrity.

“We’d never seen anything like this,” Markowski said during his presentation. “Our field project basically became a reality show in some ways. They made scientists out to be characters in this show. We’re not used to this publicity. Everywhere we went there were microphones.”

Searching for answers

Today, as the team continues to examine the VORTEX2 data, experts hope to find signatures that could one day help them better predict when a thunderstorm is about to mutate into a tornado. So far, there are theories, but no answers.

“Even though we kind of understand the big picture, we’re still today not able to look at a storm and say, ‘Okay, 10 minutes from now, this storm is going to make a tornado that lasts for seven minutes and will have a peak wind speed of 246 miles per hour.’ We’re nowhere near able to be that precise.”

Looking far off into the future, though, Markowski believes it will be possible one day to stop a tornado in its tracks.

“The history of the human race has proven that as long as you don’t violate fundamental laws of physics, eventually we can engineer just about anything,” he said. Maybe finding a way to cool down an entire city could fend off a tornado, he suggested. Maybe changing the contours of a landscape could redirect its fury.

“It would be crazy to think that 5,000 years from now we’re still losing people to tornadoes,” Markowski said. “I think, eventually, this will be the way we look back at some illnesses from 500 years ago that today are trivial.”