I was going to school at UMKC and had a ticket for this show. When I learned it was cancelled because of the roof collapse, I drove across the state and watched them in St. Louis the next day, June 7, 1979. I'd actually seen the concert at Kemper Arena in Kansas City about 9 months earlier on September 27, 1978. Incredible band.
I had tickets for this show and it would have been my first time seeing Yes, so definitely a disappointment for me. But, I think it would have been a bigger disappointment if it had happened the night of the show!
I did find this link with lots of details on the roof collapse. It does indicate no one was there other than maintenance people. The local promoters did try to move it elsewhere, but weren't able to.
[Link] next time I had tickets for a Yes show was Oct 1, 1980 in Tempe, AZ, which got cancelled due to low ticket sales. It is not listed on here, and I found a listing at YesGigs, but it doesn't note it was cancelled.
Neither previous poster is correct as to the reason the roof collapsed. It was not from the downpour, nor from a tornado. It collapsed due to a structural flaw in the roof design. When the custodian opened the doors, there was a big pressure differential between inside and outside the arena. The roof lifted up, then collapsed on the way down. I had great tickets and I never got my money back!
The concert wasn't cancelled because of a Tornado, it was cancelled because the roof was unable to drain away the torrential downpour that evening.
The storm happened three days before the show, and they tried to move it into the smaller Municipal Auditorium, but that venue was booked for the commencement of Paseo High School.
I had thirteenth row on the floor for that show ...
Was the Ten True Summers Tour the one with the disaster in Kansas City? I was to see Yes in the round but I can't remember the exact year - 1978 or 79 - but the night before the show was to take place, the roof of Kemper Arena fell in. I don't think Yes came back to Kansas City for a long time after that. Does anyone remember the news about Kemper Arena caving in? I just wondered if any equipment had been lost or what the reactions of the band were to that event.