Researchers at Princeton University consulted models and observations of an extreme thunderstorm that hit Baltimore in July 2004 and found that about 30 percent more rainfall occurred in the city than would have if there were no buildings where the city now sits.

During the storm, Baltimore experienced as many lightning strikes in the space of two hours as the city normally sees in a whole year, with much of the lightning striking the western edges of the city.

"It's as if all of a sudden the lightning can 'feel' the city," said Princeton graduate student and study author Alexandros Ntelekos.

 Source : Live Science