Professor Rongjia Tao of Temple University was speaking at an American Physical Society meeting last week that spending US$16bn on the walls would save billions of dollars every year in damage to property.
Violent tornado attacks in Tornado Alley are starting from intensive encounters between the northbound warm air flow and southbound cold air flow. The area lacks east-west mountain ranges to weaken or block the air flows.
Some encounters are violent, creating instability, he said. The strong wind changes direction and increases in speed and height, creating a violent vortex in the lower atmosphere. When the rising air tilts the spinning air from horizontal to vertical, tornadoes with radii of miles are formed and cause tremendous damage.
Tao said that the walls would behave like mountains, preventing the winds from building up to form tornadoes.
"If we build three east-west great walls in the American Midwest, 300m high and 50m wide, one in North Dakota, one along the border between Kansas and Oklahoma to east, and the third one in the south Texas and Louisiana, we will diminish the tornado threats in the Tornado Alley forever."
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