On the second day of Lollapalooza 2012, the music festival was suspended for the first time ever and thousands of people were forced to evacuate due to heavy rain storms.

As over 100,000 gathered for the music festival on Saturday, temperatures hit the mid-90's and the air was fill of humidity.  However by 3:30pm, announcements were made that strong storms were heading in and the festival would be closed until further notice.

Members of the Chicago Police Department then evacuated the 60,000 concertgoers and 3,000 staff members who were at Grant Park at the time. The attendees were directed to underground evacuation and shelter sites on Michigan Avenue as bands packed up their equipment.

"Our first priority is always the safety of our fans, staff and artists," Shelby Meade, communications director for C3 Presents, the promoter behind Lollapalooza, said in a statement. "We regret having to suspend any show, but safety always comes first."

Despite disappointment, the evacuation went pretty smoothly.

"We want to thank the tens of thousands of festival goers, staff, and artists who calmly and safely exited from Grant Park today," Charlie Jones, partner of C3 Presents, the promoter for Lollapalooza, wrote on the festival's site at the end of the incident. "We also applaud and thank the City of Chicago for their cooperation and commitment to making Lolla a safe and enjoyable experience for all. Once again Chicago has come through and we're proud to call the city our partner."

Wind, rain, thunder and lightning hit the area for about an hour, but the park remained closed for two and a half hours. At around 6 p.m., the park was reopened and the bands continued on under a new schedule. They were also given a slightly later curfew to try to make up for the lost time. The headlining acts, the Red Hot Chilli Peppers, Frank Ocean, Santigold, and Avicii were allowed to play until 10:45, just before the noise restrictions for the park were put in place.

Only a few acts were cancelled on Saturday including Temper Trap, Alabama Shakes, Chairlift, the Dunwells, B.o.B., J.J. Grey and Mofro, and Paper Diamond.

Some bands took to Twitter to keep their fans informed, such as Red Hot Chilli Peppers who wrote "the word we have is that we are still going to play."

The park was closed before the storms arrived as a safety measure. In August 2011, a thunderstorm that hit the Pukkelpop music festival in Belgium caused a stage collapse, leaving five dead and 70 other injured. The rest of the festival was called off. At the Indiana State Fair, strong winds caused another stage collapse during a Sugarland concert in August 2011. The incident killed seven people.

The Lollapalooza attendees were not given a refund.