Earlier this year, the city of Chelyabinsk, Russia, received an unwelcomed visitor in its airspace - a meteoroid that exploded high over the city. The blast broke windows, injured over 1,000 people, and served as a reminder that our planet is a target in a cosmic shooting gallery.

It was discussed as part of one of this year's near miss asteroids, one from that same day. I believe they upped the tonnage of the rock in Russia and say it exploded with several megatons and it was that shockwave, not sound waves from a sonic boom, that caused much of the damage. It was an air-burst event without the electro-magnetic pulse an A-bomb would have generated (Or would they? one now wonders).

See: http://www.funtrivia.com/forums/ubbthreads.php/topics/967278/2012_DA14#Post967278