Why shouldn’t we open windows when a tornado threatens?

Dear Tom,

I’ve heard that one should not open windows when a tornado threatens. Why not?

Bob Studholme,

Dear Bob,
It was once believed that sudden air pressure reductions that occur when a tornado moves over a house would cause the structure to explode, but that this could be lessened or prevented by opening windows to allow air to escape from the structure. This notion perished with observations of the damage caused by a massive tornado that struck Xenia, Ohio, in 1974. Opening windows was further debunked in an engineering study, in 1977, that showed conclusively that buildings do not explode because of rapid decreases in air pressure around the structure. The actual cause of damage is intense wind and wind-driven debris striking the structure. The time spent opening windows is much better spent seeking shelter.