Why do tornadoes not hit cities?
Tornadoes are not diverted by any structure or terrain. Tornado strikes on large cities seem less common only because there are few cities relative to the size of the rural areas in the U.S. "Tornadoes have picked up objects and people and set them down without damage or injury."
What are the odds of a tornado hitting your house?
A second opinion according to BookOfOdds.com "those odds [of being hit by a tornado] are 1 in 4,513,000.