Stage collapse at a political rally in Mexico
- Thread startergafftaper
- Start date
In the video below you can see it was steadily windy before the failure and the video wall was kicking forward before the collapse. Looks like there was a sudden violent gust that did the structure in.
Toggling through the historical weather data, not only did this happen yesterday, but it appears to be a trend in the area on a regular basis. Just by randomly looking at days in the past couple weeks, I see at least a half-dozen occasions of this for sudden gusts out of the blue. Possibly because they're next to some mountains. I wouldn't put much stock in the 29mph below -- from the video that gust looks stronger. Weather stations north of the area reporting gusts as high as 48mph.
Toggling through the historical weather data, not only did this happen yesterday, but it appears to be a trend in the area on a regular basis. Just by randomly looking at days in the past couple weeks, I see at least a half-dozen occasions of this for sudden gusts out of the blue. Possibly because they're next to some mountains. I wouldn't put much stock in the 29mph below -- from the video that gust looks stronger. Weather stations north of the area reporting gusts as high as 48mph.
In the various still pictures and the new, fancy moving pictures... I've seen precious little that looks like guying wires. At least in Indiana they had guys, ineffective as some were after the Fair had the staging company move the upstage anchors.
Not much about weather happens without some indications that conditions are favorable for negative types of weather occurrences. Often the meteorologists know that pressure, water vapor, and temps will present such conditions and issue WATCHES. I'm pretty sure that meteorology is Mexico is much like it is elsewhere, and the biggest contributions to the loss of life here was wishful thinking and willful ignorance.
Not much about weather happens without some indications that conditions are favorable for negative types of weather occurrences. Often the meteorologists know that pressure, water vapor, and temps will present such conditions and issue WATCHES. I'm pretty sure that meteorology is Mexico is much like it is elsewhere, and the biggest contributions to the loss of life here was wishful thinking and willful ignorance.
Appears there were a fair number of guy wires, but how adequate they were is impossible to know -- and all the guy wires in the world won't do much if that video wall is swinging in the wind like a sail. The direction of wind looks like it hit that video wall square on.
Don't they usually have long, thick, heavy steel spikes into the ground to hold the guys? Otherwise you'd be looking at several tons of ballast per guy wire (i.e. more than the wire's breaking strain) to avoid the whole shebang taking off. Like it did. I'm thinking of the huge spikes they use to anchor big tops and the like.
I don't see anything about the construction that jumps out at me as obviously wrong. What is painfully obvious is that they either didn't have, or weren't implementing, their high wind action plan.
It does look like the wind level was rising rapidly, but it was blowing pretty hard at the start of all of those videos. It breaks my heart.
It does look like the wind level was rising rapidly, but it was blowing pretty hard at the start of all of those videos. It breaks my heart.
Sugarland in Indiana had 2300 pound concrete ballasts sitting on pea gravel.
Wouldn't the gravel act like ball bearings, reducing the coefficient of friction, actually making the ballasts easier to move?
Those were K-rails, right? I've heard the "standard" is the mafia block, a 3'x3'x3' cube of solid concrete weighing about 2T (4000 lbs.), with rebar "handles"/anchor points.
Derek, the person I was talking to actually used the term 'Jersey Blocks'. I've only ever heard the highway divider thingies called Jersey Barriers. Yes, the point the person I was discussing this with was making is that they just slid across the gravel. Also, apparently the 'ground' in the stage area was new solid on top of the mud bog area.
Somewhere I have the Thorton-Tomasetti forensic engineering report of the Indiana State Fair blow-down, and the Witt Associates review of the Fair's emergency operations plans. T-T identified a number of deficiencies that individually would be catastrophic depending on how the failure initiated. The loss of upstage guy anchoring was the initiating failure in Indiana. My recollection is the Fair wanted to add another lane of vehicles back stage (trucks, buses) and had the staging company extend the guy points further up stage where there were no permanent anchorage points and Jersey barrier was used. Not every piece of barrier was on gravel, so T-T did pull testing on wet gravel, wet asphalt, and maybe wet grass. It took surprisingly little lateral force to move the ballast, and once the guy lines took slack the structure was doomed to gravity.
Ballasts were water tanks. Hard to know how many were there in total since they were tugged by the collapse and possibly cleared away as part of the rescue operation.
Eye-balling it from other images, the video wall appears maybe >2x the size of the one at Sugarland, which is a considerable force swinging in the wind as a sail/pendulum. Possibly would've failed anyway even if they had dropped only the video wall earlier in the night.
Eye-balling it from other images, the video wall appears maybe >2x the size of the one at Sugarland, which is a considerable force swinging in the wind as a sail/pendulum. Possibly would've failed anyway even if they had dropped only the video wall earlier in the night.
That was my thought, too.
Yes, that's exactly what happened.
I don't know what kind of weather warning systems Mexico has, but severe winds don't just happen out of nowhere. In the US, the National Weather Service forecast offices are staffed 24/7 to issue warnings and watches for potentially hazardous weather. Any time a temporary, outdoor structure is put up, and there are people around it, someone needs to be designated to monitor for weather warnings. In most places, the simple way to do this is a weather radio with an alert function.
It's becoming more common for large events to hire a meteorologist to be on duty. A friend of mine retired from NWS and does it quite often.
It's becoming more common for large events to hire a meteorologist to be on duty. A friend of mine retired from NWS and does it quite often.
One of TT's finding in Indiana was that they had no understanding of the structure's limits which made it challenging for event organizers to understand where the cut-off threshold needs to be in spite of any meteorology reports they may have been receiving. That's in no way any excuse, but it puts a lot of pressure on whoever's making the call if they don't know the breaking point. Whereas if you know the structure will at risk at a certain threshold, it's no longer an emotional decision a dozen people are going to argue about. The process becomes much more black and white.
In Mexico, Maynes (the presidential candidate hosting the event) described it on TV as a freak gust of wind that couldn't be predicted which is about what you'd expect a politician to say, but my understanding was that there were some degree of high wind warning, and like I said in a prior post though -- historical weather data seemed to show sporadic gusts at similar times of day several times in the last few weeks so there's a good chance this wasn't an uncommon weather event in that area from air coming out of the mountains.
In Mexico, Maynes (the presidential candidate hosting the event) described it on TV as a freak gust of wind that couldn't be predicted which is about what you'd expect a politician to say, but my understanding was that there were some degree of high wind warning, and like I said in a prior post though -- historical weather data seemed to show sporadic gusts at similar times of day several times in the last few weeks so there's a good chance this wasn't an uncommon weather event in that area from air coming out of the mountains.
