Some Americans support building a wall across the southern border of the country to keep out illegal immigrants. Now one physicist has come up with a similar idea, but for a totally different kind of threat: tornadoes.

Physicist Rongjia Tao of Temple University believes that by building three "great walls," each nearly 1,000 feet high and up to 100 miles long, that the barriers would act like hillsides, softening winds and forestalling the formation of tornadoes, reports the BBC. He recently unveiled his idea at the American Physical Society meeting in Denver.

"If we build three east-west great walls, one in North Dakota, one along the border between Kansas and Oklahoma, and the third in the south in Texas and Louisiana, we will diminish the threats in Tornado Alley forever," said Tao.

The great north-south corridor that exists between the Rocky and Appalachian Mountain ranges is the region most terrorized by tornadoes in the world. Tao believes giant walls could break up the clashing streams of hot southern and cold northern air that wisp through the area during tornado season. The walls could be designed in a variety of ways so that they don't become an eyesore; instead they could become one of the world's great architectural wonders.

"Our tornado wall could even be built of glass too. It could be a beautiful landmark," explained Tao. "I spoke to some architects and they said it's possible. It would take a few years to finish the walls but we could build them in stages."

Tao points to China, the country which houses the original Great Wall, as an example of how implementing his plan could work. Like with North America, China also has flat plain valleys running north-south, but tornadoes are rare there. The reason, claims Tao, is that China's valleys are broken up by a series of east-west hill ranges.

He also cites varying microclimates within America's tornado alley as evidence for his plan.

"Washington County [in Illinois] is a tornado hotspot. But just 60 miles (100km) away is Gallatin County, where there is almost no risk," explained Tao. "Why? Just look at the map - at Gallatin you have the Shawnee Hills."

Tao has already been testing his idea using computer simulations, and soon plans to build physical models for testing in wind tunnels too. All in all, he estimates that the total cost of building the walls would be about $16 billion. That cost could easily be made up through the prevention of tornadoes, which cause billions of dollars in damages each year.

The ambitious plan has certainly drawn its fair share of critics. Harold Brooks of the National Severe Storms Laboratory said the great walls "simply wouldn't work," citing the tornadoes that regularly occur in parts of Oklahoma, Arkansas and Missouri despite the presence of east-west hill ranges there.

Joshua Wurman of the Center for Severe Weather Research also dismissed Tao's proposal, saying: "Everybody I know is of 100% agreement - this is a poorly conceived idea."

"From what I can gather his concept of how tornadoes form is fundamentally flawed. Meteorologists cringe when they hear about 'clashing hot and cold air'. It's a lot more complicated than that."

Even if the walls succeeded in preventing tornadoes, critics warn that there could be unpredictable side effects just as dangerous as the tornadoes. The entire climate of the region could be altered, and it could present impassable barriers to wildlife. Of course, it's also still possible that the walls would have little effect on tornadoes at all, which would make them a very expensive failed experiment.

"Don't get me wrong, I'm open to new ideas. I consider myself an out-of-the-box thinker. But just because an idea is heretical, doesn't mean it's a good one," added Wurman.

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