Physicist: Building giant walls could prevent tornadoes

Imagine three east-west walls, 150 feet thick and 1,000 feet high, one in North Dakota, one along the Oklahoma-Kansas state line, and one from south Texas into Louisiana.

A physicist at Temple University, Dr. Rongjia Tao, thinks those walls could effectively eliminate Tornado Alley.

The plan would have a hefty price tag -- Dr. Tao estimates about $60 billion per 100 miles.

And perhaps more to the point, a lot of tornado experts say the walls simply wouldn't work.

Tao argues that tornadoes form when cold air from the north clashes with warm air from the south, and his walls would prevent that from happening.

But experts call that simplistic notion of how tornadoes form "nonsense," and point out that killer storms often form in areas with very little temperature difference.

In a USA Today article on the plan, Harold Brooks of the National Severe Storms Laboratory in Norman says "this is essentially a case of a physicist, who may be very good in his sub-discipline, talking about a subject about which he is abysmally ignorant."