The appearance of the falling ice signs reminds me of the day back in 2018 when the buildings became weapons. No one was injured but the scenes were dramatic to say the least.
An explanation from an article I read in Crain’s Communications at the time:
David Kristovich, a scientist with the Illinois State Water Survey at U of I’s Prairie Research Institute, said the Chicago area experienced a bit of a warm-up on November 29 after several days of post-snowstorm coldness, low clouds and periods of precipitation. He said temperatures briefly rose above the melting point. “The abundant moisture in the air and temperatures near and below freezing may have allowed the ice to form and remain on the sides of the buildings.”Crain’s Chicago Business