700 people were killed a few days ago at one of (or possibly the) most challenging crowd control events in the world - the Haj in Mecca.

How does this happen, and how can you protect yourself?

Love Parade Music Fest - Germany, 2010 -

See entire article at - http://content.time.com/time/health/...118142,00.html

Excerpts -

No one has ever been sure of exactly how many people attended the Love Parade music festival in Duisburg, Germany on July 24, 2010. The original estimate was 800,000; police later revised that down to 400,000. Either way, it was far too many: the site could safely accommodate only 250,000.

The disaster, Helbing and Mukerji conclude, was less a result of human error — though that was surely at work too — than of "amplifying feedbacks and cascading effects, which are typical for systemic instabilities." In other words, they wrote: "Things can go terribly wrong, in spite of no bad intentions from anyone."

Once a crowd gets jammed that tightly, a number of behavioral factors come into play. First, a need to flee. "The density, noise and chaos in a ... crowd cause a natural desire to leave," the authors write. This is made worse by the fact that while it's easy to see the general direction a mass of people are moving if you're even a few feet above them, when you're part of the scrum, you're essentially blind. That leads to anxiety — which is a short step from fear, which is a very short step from panic.

Human bodies moving en masse have been compared to fish in a school or molecules in water, but the better analogy is to fine grains in a stream of sand. One body pressing up against another exerts a force, which is added to that second body as it presses up against a third. This leads to a rapid accumulation of weight and energy, which propagates quickly and violently in all directions. "At occupancies of about seven persons per square meter, the crowd becomes almost a fluid mass," the paper explains. "Force chains may form [leading to] an uncontrollable kind of dynamics, which is called crowd turbulence or a crowd quake."

The power of such a human temblor is hard to overstate. Victims can be lifted out of their shoes and their clothing is often torn away. Compression makes breathing difficult — a problem exacerbated by the accelerated respiration that comes with panic — and while people killed in a stampede are often said to have been crushed to death, what typically kills them is asphyxiation. As more people succumb, they go limp and fall, which leads to a cascade of stumbles and pile-ups. People at the bottom of the resulting heaps may asphyxiate too from the sheer weight of those on top of them.

Black Friday Wal-Mart Crowd Crush - 2008 -

Entire article at - http://content.time.com/time/nation/...864855,00.html

Excerpts -

"How could you know something like that would happen?" one worker told the New York Times. "No one expected something like that." But for people who study crowd crushes, there was nothing surprising about what happened at Wal-Mart. It was reminiscent of many tragedies that have come before, at soccer stadiums, concerts and Ikea stores, which only makes it more awful. "We know exactly how crowds work," says G. Keith Still, a crowd management expert who has helped plan high-density events around the world, including the annual pilgrimage of Muslims to Mecca in Saudi Arabia. There is, he says, no excuse for these kinds of accidents. "It's stupidity. It's ignorance. But the consequence is human life."

But here is what we do know about crowds, generally speaking, and none of it is as malicious as we might expect.

1. Competition kills.

It's possible to have bargain bonanzas without casualties. But it's imperative to make the process fair and predictable. If, for example, people wait in a snaked line with ropes or are given numbers, then they know in advance who goes first — and do not feel the need to compete when the doors open. "Allow those who have waited longest to get in first," says Still. "Let them in one at a time. Then everyone knows it's a fair system. Very quickly you see that people's behavior adapts."

Police have said that the Wal-Mart incident may have happened after people who were waiting in their cars tried to rush the doors, past people who had been waiting outside.

The most notorious example of this problem, called a "craze" by crowd management experts, happened at a Who concert in 1979. A crowd of 18,000 fans had gathered outside the Cincinnati Coliseum to see the band. Seats were on a first-come, first-served basis. When the opening band began to play, the fans thought the show was beginning without them. There were only two doors open, and the crowd rushed toward them. Eleven people died.

2. Crowds are deaf and dumb.

It often looks like a crowd has intentionally trampled the victims. But what usually happens is that the people in the rear of a crowd do not know that someone in front has fallen. They still have room to move, unlike the people in front, so they continue to press forward. The compounding pressure can bend steel like it's made of rubber. "It only takes five people to push against one to break a rib, collapse a lung or smash a child's head," says Still. Most stampede victims (including the Wal-Mart worker) die of asphyxiation — they literally cannot breathe due to the pressure of the crowd.

At an outdoor 2000 Pearl Jam concert in Denmark, nine people were killed when the fans in back surged forward — despite band members' pleas to step back.

3. Physics matter most of all.

When crowds are moving, there should be no more than two to four people per square meter to prevent injury. It's a simple mathematical reality. Otherwise, people do not have enough room to recover from being jostled. Someone can easily fall. Then someone else will lean down to help that person and get sucked down, too. The pile up begins, absorbing the growing pressure of all the people coming from behind.


Once a crush begins, it's very hard to reverse the flow. So it's essential that event organizers preserve enough space anywhere the crowd may flow. At Hillsborough Stadium in the U.K. in 1989, a terrace became packed with fans, causing a railing to give way. In all, 96 people died. On the terrace, there were 8.4 people per square meter, according to studies of photographs taken before the railing collapsed.


Many huge crowds passed into stores without incident on Black Friday. "Disney World does this every day," notes Nassau County Police Commissioner Lawrence Mulvey. "People aren't inherently interested in hurting each other." But managing crowds is not something people do well without knowledge and training. Mulvey says that his department met with local retailers, including Wal-Mart, two weeks before Black Friday to remind them that they needed to provide their own security. "We patrol the parking lot, the exteriors, but each individual store is responsible for their own security," says Det. Sgt. Anthony Repalone. "We can't be at every retail store, especially on Black Friday."

I avoid crowds.

Couldn't say it better, just don't be there.

Here are a few survival points I got from this:

1. Identify a dense crowd and avoid it.

2. Being tall or being able to see a few feet over the crowd helps to identify the crowd movement.

3. How strong or athletic you are does not matter if you are unlucky to be at the wrong place in a stampede.

I agree! Unpleasant at best, deadly at worst…forget it!

I don't understand why anyone would join a crowd in the first place, no matter what the reason for the crowd gathering. If I ever accidentally end up in a forming crowd, I get out of there, fast, before anything bad happens. Sometimes it is difficult - for example, we have season tickets to our NHL hockey team, and there is always a crowd bottleneck getting into the arena doors. In that case, we go to the farthest outside line, and once inside, go to the farthest and least used (read: "least convenient") metal scanning location. It's too bad they recently put up those scanners. It really bottlenecks things and backs up large crowds. They don't do any good. Just a "feel good" thing for some people.

Correct, they absolutely don't. I recall metal detectors at a Spartan Race at AT&T park. I had a man bag, which didn't go through the metal detector (the reason, I do not know). Because I was wearing runner gear (or because they didn't care), they didn't check my bag. I could have had anything in there. I did have a pocket knife.

The thing is, if you want to create havoc, when inside the sports arena it's really big and seats are spread out. You could do a lot more damage out there amongst the nose-to-nose crowd crammed together trying to get inside through the security gates. Same thing goes for airport security. How many people on a typical plane? 200 maybe? How many standing in a crowded mass of people waiting to take off their shoes and display their toothpaste to make it through security? 500? 1000?

.

Depends upon the airport. That is why I utterly despise LAX and prefer to fly out of the smallest. Rapid City, SD is so much better... Smaller crowds....

This reminds me of enrollment day at my first day of high school. Some genius administrator decided that it would be a good idea for the students to do a mad scramble inside the commons area trying to sign up for their classes on a first come-first serve basis. With only one entrance to the great hall open, and 600+ students waiting outside in a large crowd to get in as soon as the staff said go, it was a disaster waiting to happen.

First, all the upper classmen were allowed to sign up a day before us. Since many of them had not taken the pre-requisite and "mandatory for graduation" classes they were supposed to take in previous years, they had taken vacancies that were to be allotted for us. This meant that there would not be nearly enough seats available in those classes, which put some physical competition into the mix. A number of false starts put the crowd into a huge surge a number of times, resulting in more than a few people getting stepped on, knocked down, groped, hit, and so on. Unfortunately, I found myself smack dab in the middle of this fiasco.

Luckily, I was one of the tallest kids in our grade, so when the body pressure came, I was squeezed out to the top of the pile and avoided getting hurt. Unluckily for those standing around me, they had to bear my weight as there was simply no place for me to go but on top of them. This went on for a good 10 minutes or so, as more people ended up on top and underneath the mass. All the while, the idiot staff were screaming at us to control ourselves. This was the year when Pink Floyd's "The Wall" came out and so the irony was severe.

Needless to say, registration was a complete mess. Frustrated students and irate parents spent the next 6 months complaining to the school board and trying to find some solution. I ended up graduating with 35 out of 36 possible semester credits, because I could only take 5 classes my first year in. It was enough to graduate, but my folks were not impressed.

It took another two years for the administration to finally capitulate and go back to actually working with the students to help them get registered. I think the last go-round 3 kids ended up headed to the hospital in ambulances.

No one ever said educators had a lick of sense.

I just finished reading Ripley's "Unthinkable" . In addition to the "Competition" factor in crowd crushes, there's also crowd direction. If the crowd is headed in more then one direction, it aggravates the crush. In mt observation, there are three factors that need to be present for crowd crush. First, is crowd density. Second, is there needs to be some urgency. The last ritual of a weeklong pilgrimage, first come first serve resources, or a concert that's already underway. Lastly, is something to slow the crowd. A narrow passage like an entrance or exit or another crowd headed in a different direction.

Outside of outright avoidance, I don't know how to deal with crowds.

as an update, they've raised the fatality totals

Last body count is 1100. Roughly the same as the General Slocum disaster in 1904. More details are coming out as well. Like the General Slocum, it's not a single cause, but a cascade of mistakes

1) A group of 300 pilgrims departed the bridge early without being cleared to do so. They proceeded east on street 204, and intersected a group of 5000 going south on street 223 toward the bridge. Street 223 terminates at street 204, and the pilgrims on 223 would have to have gone west on 204 to reach the bridge. Fences lining the road prevented escape into the surrounding tent city.

2) Scheduling on the Jamaraate Bridge is notoriously tight, and as such, not very tolerant of out of position groups.

3) Street 206, which is the next intersection north on street 223, was blocked off. 206, if open, would have provided a relief path from the group headed south on 223. Why 206 was closed is still under investigation. The Iranian and Saudi goverments, not real friendly at the best of times (differing sects of Islam), are offering different reasons.

4) It was 47C (~117 F) at the time, which may have contributed to the early departure at the bridge.

5) Concerns about training of the Saudis in regards to crowd control. Specifically, why they were unable to compensate for the rouge group of 300 before it covered the 600M distance between the bridge and the intersection.

According to this , the number is now at 2,121.

When captured in such a dense crowd where you cannot even turn around - start breathing deeper, moving your chest up and down, instead of usual shallow diaphragm breathing. Try to keep the lungs half full all the time. Keep one of your palms locked over tightly closed fist under the chin, pressing the fist at the clavicles, and spread your elbows out a little at the chest level, like making a cage for your chest. Avoid spreading your legs too much while walking pinched between people, your leg might be captured tightly. If about to fall over something or somebody on the ground - use elbows to hang over the neighboring people and rise both legs over the obstacle, or step on it. If cannot withstand the pressure anymore push into others in perpendicular to the "crowd wave" direction (usually it goes along the "to the stage" or "to the exit" line), or even try to climb up a bit on your elbows, you are thinner down the legs, and people most likely will try to knock you off back, giving you some space for that. Been there done that.

In my experience, I found that climbing up on top of the crowd, spreading my arms and legs a bit, and either crab walking or rolling over the top to be quite effective. The people under me didn't like it much, but I got to the edge of the mob and was able to egress to safety. People were packed so tight that even if they wanted to they had no room to pull me back down once I got on top. Of course, there are caveats to such endeavors, but staying in the middle was simply no longer a viable option.

YMMV