Lollapalooza got off to a soggy start today as the first of what is expected to be a wave of storms skirted Grant Park and pelted festivalgoers.
The rain quickly moved to the south but some of the fields for the concerts were left muddy.
Forecasters say the Chicago area could get hit today by the heaviest rains since late June.
There is more than enough moisture in the atmosphere to fuel steady downpours and clusters of thunderstorms. But this is summer and warm season rains are notorious for being unpredictable. People in some areas could be drenched while others watch the downpours pass them by.
The rain this morning is expected to clear by midday. But clusters of storms could blossom late in the afternoon and early evening. The first act for Lollapalooza begins at noon.
Organizers have updated their severe weather plans to ensure fans know where to take shelter. Last year more than 60 000 festivalgoers were evacuated but many said they received no information about designated city shelters.
Lollapalooza's weather plan both the 2012 and 2013 versions calls for city workers to direct concertgoers to the garages as they're exiting Grant Park.
Melissa Stratton a spokeswoman for the city's Office of Emergency Management said people in the crowd did receive that direction last year but opted to wait out the storm elsewhere. Nevertheless Stratton said as part of the planning process we are working with C3 and CPD to strengthen crowd communication outside the venue.
C3 also is taking extra precaution this year to make sure those at the festival know the shelter locations. This year the main entrance on Michigan Avenue between Balbo Avenue and East Jackson Drive will feature video screens that can be rotated in order to broadcast messages to the crowd C3 spokeswoman Shelby Meade said. Signage directing fans to shelters will also be on hand in case of an evacuation.
Meade said tips featured on the festival website will also include the locations of shelters and the information will be distributed via social media in the event of an evacuation.
Concert promoters and music fans got a tragic reminder of the power of weather in August 2011 when a stage structure toppled over into the audience of a Sugarland concert at the Indiana State Fair amid high winds.