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Horrible tragedy shows how quickly conditions can change during severe weather

  • Thread starter Thread starter Jordan Hartley
  • Start date Start date
From a design perspective...there was no reason that a structure could have been designed and built to withstand conditions. Bottomline is that the structure should not have fallen PERIOD. I don't care if there was a warning or no warning, whatever. Even if no one was hurt, the thousands and thousands of dollars lost from broken equipment, delay in the show, lost ticket revenue, etc. While life safety is paramount, there is more to structures than just 'surviving a storm'. The simple fact is it was poorly designed and/or constructed....PERIOD.
 
After watching the video on youtube I am amazed at the amount of people that are in front of the stage right before the gust front hits. The gust front was typically stronger than what one would expect that far out ahead of the line, but even without the gust front it *was* obvious that the line of storms was going to eventually hit the area soon and preparations should have been made well in advanced before it hit. I am no structural engineer but it seems that the stage may have been too top heavy perhaps and also not anchored with enough guide lines. The stage should have been able to withstand those type of winds especially considering there were no other reports of damage to any of the other tents/structures at the fair.
 
A similar situation happened at the EAA fly-in convention in Oshkosh this year while I was there. A gust front hit right in the middle of the airshow with thousands of people gathered at the flight line. Lawn chairs, cups, and other items people brought out to the grounds were sent tumbling across the field, and people were scrambling for cover. Crappy cell phone pic as it hit:

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There are a ton of temporary structures along that field including tents, stands, and pavilions, and at least one of the tents came down damaging a bunch of scooters that were parked underneath it. I didn't think much of it at the time, and actually thought it was quite amusing watching everyone scramble for cover. The tragedy in Indiana really made me think of how serious a situation that could have been though. These temporary structures are just not built to withstand the same kinds of forces that well constructed permanent structures are. People need to recognize that gust fronts, even with winds well below severe criteria can pose a serious threat to these structures and the people underneath them.
 
Something I wondered about: could the stage collapse have been caused by a gustnado?

http://www.accuweather.com/blogs/news/story/53798/indiana-stage-collapse-gustnad.asp

I looked at the videos over and over and thought there could have been some rotation in there, but it could also have been eddies or direction changes caused by wind going around the stage, grandstand, etc. I don't think that its being a gustnado would change much in the issues being discussed here, since gustnadoes occur along gust fronts that in a storm this strong are dangerous in themselves - but a gustnado might help explain the rather localized nature of the damage.
 
Maybe, but you're looking pretty hard to find that. I didn't hear anyone say they saw a funnel touching down, and with 12000 people there you think someone would have snapped a pic.
 
My view is 90-100% blame should go to the structural integrity of the stage. A few thoughts/observations:

- This appears to be a fairly routine severe/borderline-severe MCS gust front event for the Midwest in the summer. These happen almost every day somewhere in July and August from the Dakotas to Ohio. Severe wind+outdoor stage encounters are probably common and numerous during the summer, without incident.

- LSRs show very few damage reports from this event in the Indianapolis region. Significant severe winds typically cause widespread damage reports, downed trees and power outages.

- I doubt that winds in the video are reaching 70mph or even 60mph. Video shows no other tents/large airborne debris indicative of significant severe winds. The stage is the only casualty. Large amounts of dust and small debris are common during gust front winds of 40-50mph or lower - I see it a dozen or more times a year.

- The stage was top-heavy, lacked basic cross-bracing structural members, was covered with a wind-catching solid tarp, and appeared to go down almost immediately as the winds began. Photos showed tensioned guy wires, but apparently they were not adequately anchored.

Contributing to the event was the fact that no one apparently recognized the radar-visible outflow ahead of the storms nor the approaching shelf cloud, instead relying totally on the precip core reflectivity for the storm's position. However, notwithstanding, I think the primary blame by far has to be the poor construction of the stage. When setting up such a structure in the Midwest in the spring or summer, there's no excuse for not planning for winds in storms such as these.
 
Another factor that seems to have been in play is the tension or disconnect between the public safety people whose instinct is to delay or cancel the show, or tell everyone to evacuate, vs. the concert organizers whose instinct is that "the show must go on" if at all possible.

Apparently, the fair staff HAD decided to evacuate people but the concert announcer was less categorical and told the crowd that he would let them know IF they were told to move to shelter.

Obviously the concert organizers don't want to give up on the show until they absolutely have to, given the number of people who have paid good money to see it, and they may have figured that as long as it wasn't raining and lightning wasn't striking nearby there was still a chance the storm might miss them and the show could proceed. They also probably assumed that with the main storm still some miles away, they still had time to make a decision. It was in that moment of indecision that the gust of wind hit, and then it was too late.
 
Was at Nascar here in Chicago in 08 when a gust front slammed the campgrounds. This is an event that has about 100,000 people each time. EZ-Ups went flying everywhere. However at the actual track a loud announcement came over the speakers warning people it was coming, and they were evacuated from the stands in the track. Though in retrospect, had this been a tornado there is really nowhere for people to go. They were told to go under the stands which are fine for this case but if it were a significant tornado could those stands come down? I don't know what they can handle as far as that goes. At least the people in charge seemed to be well aware of the approaching threat, but it always made me wonder what would happen if it were something more serious than a 50mph gust front.

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Good day all,

The problem with fairs (and any outdoor events) is the poorly anchored structures and vulnerable to collapse.

In the pictures below, tents and outdoor structures are blown over and scattered at a skydiving event in Rantoul, IL in 2006.

skywfc7.jpg


This storm just had 50-60 MPH gusts, but toppled the stage and other "temporary" structures ;-(

skywfc8.jpg


Above: Damage to outdoor structures / poorly anchored facilities.

The point here is not much in the way of severe winds, but how profoundly a rather "mild" severe thunderstorm can disrupt life and property in a "pop up" or temporary structure.

The bottom line is that if something collapses / is blown over (or away and creates a "projectile") ... A relatively weak wind (or a wind that would otherwise cause little damage) can KILL.
 
Contributing to the event was the fact that no one apparently recognized the radar-visible outflow ahead of the storms nor the approaching shelf cloud, instead relying totally on the precip core reflectivity for the storm's position. However, notwithstanding, I think the primary blame by far has to be the poor construction of the stage. When setting up such a structure in the Midwest in the spring or summer, there's no excuse for not planning for winds in storms such as these.

It is factually incorrect to say "no one" recognized the outflow. WeatherData/AccuWeather issued a warning at 8:23pm explicitly calling for 60 mph winds valid from 8:45 until 9:25pm for a client near the Fairgrounds. Our TOA was based on both the outflow boundary and any winds that might occur with the main area of thunderstorms as it passed over.
 
It is factually incorrect to say "no one" recognized the outflow. WeatherData/AccuWeather issued a warning at 8:23pm explicitly calling for 60 mph winds valid from 8:45 until 9:25pm for a client near the Fairgrounds. Our TOA was based on both the outflow boundary and any winds that might occur with the main area of thunderstorms as it passed over.

True - I should have clarified I was referring to those connected to this event (organizers and attendees).
 
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