Police shut down the 2200 block of San Jacinto Street after panes of glass started falling from the JP Morgan Chase building.
Only the outside glass on the double-paned windows above one another on the 18th, 24th and 32nd floors broke.
The transportation coordinator for the hotel hosting members of the Mary Kay Convention saw it happen. The convention is being held down the street and was not affected.
Building engineers are trying to figure out why the windows broke.