It rained a lot in e.g. 2014 but it was just before and at the start of the event. I don't think there was a time there was anywhere near 73k people already inside unable to leave expecting a couple of days of rain to come right when everyone was planned to head home. At best outlook, this is going to be one of the worst events to have gone to. I don't think it'll be a disaster but I would say it's extraordinary.