quasigeostrophy | Clarification & Further Thoughts on the Indiana State Fair Stage Incident

As I continue to read blogs and hear conversations among meteorologists about the storm that caused the damage, injuries, and deaths, I have thought further about what I said in my previous post on the subject. I still look at it a bit differently, and I think it has to do with my specific area of meteorological expertise. I am not a mesoscale (storms, squall lines, and such) or synoptic scale (about the scale of the typical U.S. weather map) meteorologist, and I am not a forecaster by trade, though I know a lot about it. My specialty is cloud microphysics – I look at movements and interactions, dynamics, thermodynamics, and physics of small parcels of air and water and ice, and how they form clouds and precipitation. From small-scale movements and interactions of molecules and droplets and ice crystals to entire cloud systems is my domain. I think that I am still calling the specific gust of wind that took down most of the stage “unpredictable” in one sense because it is indeed still difficult to forecast such a short-lived and localized gust in larger-scale forecast models.

Even in smaller scale models, such as the NOAA HYSPLIT model, I have run trajectories of air forward in time starting at the same point, and all of these trajectories diverge at some point in time to finish in different places, and that isn’t usually air at the surface, which interacts with trees, buildings, etc. So anyone who tells me the gust was completely predictable is talking about larger-scale dynamics. Strong winds like this were mentioned as a possibility in the NWS warning, as I posted previously. The fair midway and all of its rides, including a drop tower and Ferris wheel, only a couple hundred yards away from the stage directly to the west, was unaffected, and as far as I’ve seen reported in the media, no one in the midway felt the strong wind that hit the stage.

I also should make it clear that, despite my opinion that the neither the Indiana State Fair nor Indiana State Police should be blamed for the tragedy (from the perspective of the weather or handling of evacuation, for which I stand by my statement that adults need to take responsibility for their own safety), I completely agree with the Indiana State Fair, IOSHA, the various emergency response agencies, and particularly the company responsible for construction and management of the stage undertaking investigations into physical causes. Some have pointed out that there is no construction code for the stage under the circumstances. If that is the case, then I don’t believe the contractor should be held legally responsible, since there was no law, but a law or regulation should be introduced. Also, should investigations reveal that any of the organizations involved were negligent, then by all means blame can and should be placed at that time.

Originally published at Abnormality Locality. You can comment here or there.