Parts of Grant Park a mud bath after storms rolled through Lolla

Day two of Lollapalooza in Grant Park has wrapped up without any issues.

That was not the case Thursday night, however, as a line of heavy thunderstorms prompted the evacuation of nearly 100,000 people. It also turned parts of Grant Park into a mud bath.

A line of heavy thunderstorms rolled in over Grant Park about 9:30 Thursday night, prompting the city to pull the plug on Lollapalooza and evacuate the 100,000 fans about a half hour before it was scheduled to end. Many of those people took refuge in the underground Millennium Park garages.

"Well this is something that we practice and talk about really throughout the year,” said OEMC Director Rich Guidice.

Office of Emergency Management director Rich Guidice says they made the call at the city's command van inside the event, which is equipped with weather radar and an on-site meteorologist.

Guidice says rain itself isn't a problem, but wind and lightning are dangerous.

"Lightning's definitely a game changer. So we were watching that when it was 25, 30 miles out. And as it was getting closer we realized we had to make a decision,” Guidice said.

On Friday morning, city crews could be seen spreading mulch in low-lying parts of Grant Park to soak up the aftermath of Thursday night's storm, and covering up the mud.

This is the third time Lollapalooza has been evacuated for dangerous storms over the past five years.

"We evacuated here in 2012, 2015, almost last year, we came very close last year but we were able to keep everybody inside,” Guidice said. "Well, it's Chicago and certainly the weather changes quickly around here. But we had a good plan in place and we were ready for it last night."