Our American residents on here — I'm very careful about calling them “Yanks”, since I've been sharply reprimanded for it — would have something to say about that. It seems to me that I've seen posts confirming that pretty severe thunderstorms are regular occurrences in that part of America, at this time of the year. And there's a standard protocol for public events out in the open, since people can and do get killed.
Let's face it, the CWC is very largely about marketing, and the “brand” of football. They knew there was a good chance of this happening.
Anyway, they have weirdo things over there, like hurricanes with women's names, tumbleweed blowing down streets in the south-west, and mini-twisters that you can apparently get inside and run around in when you're a kid (was told this many years ago by a friend from Oklahoma who said that was what they did to amuse themselves).