The headlines shows played a bit later and the entire scheduled was pushed back due to the big gap in the annual music festival's second day.
At 3:30 p.m., shows abruptly came to a stop and a parade of 61,000 was ordered to evacuate.
"All of a sudden we heard some sort of weather warning or something, huge storm is coming," said Nesh Patel. "We didn't think it was real. We thought it was a joke." Lollapolooza was temporarily suspended due to severe storms predicted to go though the area.
"C3, Chicago police, fire, OEMC, Chicago Parks all got together and made that collaborative decision in the interest of public safety to go ahead and evacuate the park," said Chicago Office of Emergency Management's Gary Shenkel.
Some thought the evacuation order was premature.
"I would have be better waiting because obviously we missed a good hour we could have been enjoying ourselves," said Marvin Street. "But I do understand with recent events that people would be extra precautions."
But an hour after the evacuation was ordered that predicted storm opened up with heavy rain and lightning.
Some Indiana visitors recall the stage collapse last year that killed seven people when a storm rolled in during a concert.
"It makes sense safety wise, legally too with what happened in Indianapolis," said Jessica Navarro. "Everybody is being cautious and careful."
During the storm, some found shelter under lower Randolph with a little music from a bike taxi speaker.
Some were eagerly watching for updates from the Lollapalooza app or tweets.
As the rain lightened up, some started back to the park and at 5:45 p.m. the music festival officially re-opened.
Delighted music fans streamed through the entrance ready to start up where they left off.
But due to the lost time, a festival executive says a few bands were bumped.
"In coordination we have moved the ending of the show from 10 to 10:30 p.m., which will allow for a little bit more time, but unfortunately we had to cancel a few bands," said C3 Presents' Charlie Jones.