I posted initially about this collapse early this morning, and now did a bit more digging. The stage roof apparently collapsed around 3:30pm as Christian band "The Afters" was sound checking. A representative for the promoter said “We weren't aware that the winds were going to get that high.” As is often the case in these situations, there was plenty of warning if you know what to look for. I'm a storm chaser , not a meteorologist, but storm chasers are constantly obsessing over radar, and someone qualified should have been doing the same thing for this show. Here what the radar looked like at about the time of the sound check (19:17 UTC is 3:17 local time):
According to Wikipedia, EHO is the Shelby-Cleveland County Regional Airport, and the Cleveland county fairgrounds are a couple miles away to the north east, about the position of my crude red arrow. The light blue, bowing north-south line to the left of the purple arrow is a gust front or outflow boundary, generally caused by cool air descending from the storm and indicated on radar by reflections from bugs and dirt in front of the storm. Crucially, this gust front arrives with high wind gusts before the rain arrives (this is exactly the same situation found at the Indiana State Fair tragedy; you can see my radar loop here). So if you just watch the radar on a crude phone app and don't know what to look for, you might miss this critical feature. But it's an indication of high winds in front of the storm (as a chaser I'm often surfing this area trying to get a photo, since sometimes an amazing looking shelf cloud forms is in that area, see here for photos from a similar event from earlier this summer). Here's the whole loop of the radar, and it's pretty obvious that something's coming for quite a long time. The yellow arrow is the approximate location of the show site; with my mouse, I point out the gust front:
While another part of the same storm system was under a severe thunderstorm warning (60 MPH+ wind) at the time of the collapse, the show site area apparently was not. Patrick Moore, of the National Weather Service said that winds at the site gusted to about 35-40MPH (well below the severe threshold), which should not cause any quality stage roof to collapse. But, as I noted in the previous entry, it appears that the stage roof was supported with Genie-style towers. Those are chronically mis-used pieces of gear, and one of the common failings in amateur outdoor usage of these lifts is not accommodating for the intensity of lateral loads caused by the winds, nor the vertical lift possibilities. Joel Bench, MercyMe's stage manager, reported "The wind just picked up, the roof lifted a little bit, Then it started tilting and just kind of eased down.”
The promoter said, "We’re sad, but you can’t really stop Mother Nature." That's true, but you sure as hell can--and must--be prepared for what she doles out. I'm glad no one was hurt, but I really thought after so many tragedies (I've written about so many that I have a whole blog category for them here) people would start taking these things more seriously by now.