Tornados in the Midwestern and Southern United States have always been a troubling yet fascinating phenomenon - just think of Dorothy's whirlwind adventure in the Wizard of Oz! Occurring predominantly in the area east of the Rocky Mountains dubbed 'Tornado Alley', they form during severe thunderstorms called supercells that occur when cold dry polar air comes in contact with warm moist tropical air.

As the warm air rises, winds around the storm cause it to rotate and form a funnel. The air in the funnel spins faster and faster, creating a low-pressure area, which sucks in even more air and sometimes, even objects. While ordinary thunderstorms last between 30-60 minutes, supercells develop many updrafts and downdrafts and can live on for hours, often resulting in massive destruction.

While twisters occur all over the world, they are most common in the USA, which experiences an average of 1,200 a year. Though only a handful are truly deadly, millions of Americans live in fear every year from March to June, when the unpredictable twisters descend upon them with little or no warning.

Is there anything that can be done to protect people from nature's fury? Dr. Rongjia Tao from Philadelphia's Temple University's Department of Physics, certainly thinks so. He proposes that we build giant walls to keep the tornados at bay. The scientist's thesis is based on extensive research during which he uncovered that major tornados usually occur when winds are moving faster than 30 mph and almost never, when they are at speeds of 15 mph or below. This led him to conclude that in order to stop deadly twisters from forming, we would have to figure out how to reduce wind speed.

For inspiration, Tao turned to the mountain ranges in China that intersect east-west across the plains, naturally blocking out the north-south flowing winds. This helps protect the northern and eastern plains from severe wind storms and tornadoes, despite the otherwise twister-conducive weather conditions.

By replicating these blockades using three giant walls, each measuring 1000-feet high and 150-feet-wide, Tao believes that the number of deadly tornadoes in the Midwest and South, could be greatly reduced and perhaps even eliminated. For optimal results, he suggests placing one along the northern boundary of North Dakota, one along the border between Kansas and Oklahoma, and the third, around south Texas and Louisiana.

As with any new radical idea, this one is being met with some skepticism. Harold Brooks, a tornado researcher at the National Severe Storms Laboratory in Norman, Oklahoma, asserts that we already have east-west mountain ranges the size of Tao's proposed walls, in parts of Oklahoma, Arkansas and Missouri.However, they have been unable to stop the tornados.

Mike Smith, a meteorologist at AccuWeather Enterprise Solutions concurs and adds that if the mountains are unable to stop the supercell thunderstorms with F-5 tornadoes, walls really stand no chance. He also maintains that the theory that tornadoes are largely caused when cold air hits warm is a misconception and says that most of the violent thunderstorms occur along an area where there is relatively little difference in temperature.

Also up in arms are environmentalists who are concerned that the walls may alter the weather patterns. And then are those that are worried that the walls will not blend in with the surroundings. However, the biggest impediment to building the walls is the cost, which Tao estimates to be about $160 million USD, per mile.

Despite all the naysayers Tao is confident that his solution would be extremely effective and suggests testing it by building smaller walls around tornado-prone areas and then linking them to one another, over time. He also advises building all new skyscrapers in 'tornado alley' on an east to west axis, so that they can help create a break in the landscape and hinder tornado formation.

While Tao's proposal may be fraught with hurdles, he has brought to light an issue that needs to be addressed, especially given that experts expect climate change to result in increasingly volatile weather patterns.

Resources:usatoday.com,gizmag.com