Indiana State Fair Stage Collapse

As most of you know, a stage at the Indiana state fair has collapsed, killing at least 5 people and hospitalizing at least 45.  A Sugarland concert was planned to take place.  At this time, investigations are ongoing, and officials warn that some of the people in hospitals are in critical condition, and the death toll may rise.  A few YouTube videos are out, and they paint the picture: high winds blasted the area, causing a stage containing a few tons of metal to collapse on some people in the front rows.  We have the best one here, but please be advised that this is very high definition, and clearly shows the structure falling on top of people.  In other words, viewer discretion advised:

Horrible.  Just horrible.  Now debate is up as to whether or not it was caused by a thunderstorm, if the structure was even safe in the first place, should the police have evacuated people, etc.  We plan to answer the questions above.  First, was it caused by a thunderstorm.  Actually, if you look at the video, a few lightning flashes are visible in the distance, but it does not appear to be raining.  Since we can't get much from this, we check radar.  We can clearly see a line of severe thunderstorms bearing down on the area.  HOWEVER, at the time of collapse, the thunderstorms had not yet arrived at the park.  A closer look shows that an outflow boundary produced by the storms had moved out ahead of the line.  That explains the severe winds occurring without rain.  All storms produce downdrafts.  When these downdrafts hit the ground, they spread out, much like water hitting the bottom of a sink.  Sometimes, these downdrafts move out ahead of the storm, like what happened in Indiana.  How strong were the winds?  Winds are estimated to have been between 60 and 70 mph.  You need proof?  Look at all of the dust being blown around, the flag, and obviously, the collapsing stage.  The last question we will try to answer is "Why weren't the people evacuated?"  Well, it sounds like police had cancelled the Sugarland concert when they saw the severe thunderstorm warning, and that they were planning to evacuate soon.  People are calling the sudden gust as a "fluke," which we've determined it was not.  At this time, our best guess is that officials simply didn't expect the outflow boundary to hit like that.  Actually, people appear to be evacuating in the first part of the video, so that potentially saved more injuries.  That is all I have for you now, stay tuned!