Possibly as big as the Siberian Tunguska event.
Trajectory Unclear: Feb 2013 Asteroid Will Be Within Thousands of Miles of Earth; Impact Would Be As Big As Siberian Tunguska Event; 1000 Times More Powerful Than Hiroshima
Trajectory Unclear: Feb 2013 Asteroid Will Be Within Thousands of Miles of Earth; Impact Would Be As Big As Siberian Tunguska Event; 1000 Times More Powerful Than Hiroshima