Everyone fears the day a super tornado strikes a major metropolitan area, because a mile-plus wide tornado with winds over 200 mph could end up causing thousands of deaths in any urban area.
In 1999 the Moore Tornado was an F5 that hit Oklahoma City and its suburbs, later on the same system produced deadly tornados in the Wichita area. The scary thing is that today those two metro areas are going to be directly under the gun.
You don't consider the greater Oklahoma City area a "major metropolitan area"? The last F-5 mentioned as hitting Moore OK also hit parts of OK City. Moore is just on the southern border of OK City. It didn't kill thousands, but it did kill some, and did a lot of damage. I flew into OK City a few weeks after the tornado. The path was clearly visible from the air, even if you couldn't see the areas of major damager (I could not because we were pretty much directly over them). I could tell the path just by the downed and stripped trees. It caught the edge of Tinker AFB, and just grazed my company's OK City (actually Midwest City) office. Other offices in the complex were damaged, and our office suffered blow in windows and water damage. But that was just the tail end of the storm, although by looking at some hotels and other businesses along I-40 (which were damaged *after* the storm passed our office) you might not think so. Worst damage was miles away in Moore and nearby parts of OK City. It pretty much wiped out a shopping center along I-35 and destroyed homes and a school near there.
http://en.wikipedia.org/wiki/Tri-State_Tornado
The one that hit Xenia, Ohio in 1974 was similar...
http://en.wikipedia.org/wiki/Super_Outbreak