The NWS confirmed that it was an EF-4 that hit the airport. (EF-4 = 166-200 mph). It's been probably 20 years since I have flown out of STL, so I'm not sure how the terminal is laid out. But, I will say that I have never seen screeners move that fast.

The Enhanced Fujita rating scale for tornadoes.

FYI, my meteorologist friends tell me that the term they use for an EF-4 or EF-5 is "Pavement Puller."

Bio on Ted Fujita -- one of the true icons of severe storm meteorology.