From the Chicago Tribune Thursday, May 29th 2008:

Weather Balloon Crashes into U of C Lab

The National Weather Service today issued a formal appology to the University of Chicago, and in particular its Division of Sciences for a "regretable accident" which occured just after 1:00 pm, yesterday afternoon. According to statements from both NWS, the University of Chicago and passers-by, a weather balloon collided with the Univeristy's Interdivisional Research Building (at 915 E 57th St). A third floor window of the two-year old building was broken, but apart from that, no other damage was sustained, according to a spokesperson for the University. Pedestrian traffic ajacent to the shattered window had to be halted for a half hour while a clean-up crew worked to make the area safe. Sheryl Dempsy, publicity director for the National Weather Service expressed her "...regret, for the unforseen mechanical failure of this important data collecting instrument. At the same time, I wish to express my thanks to the University of Chicago for its patience and understanding, and to the other federal agencies whose quick response made this an embarassment rather than a crisis."