You’ll find that most people talk about crowd crush surrounding concerts and holiday shopping. The long lines that people form when moving towards something they want – or away from a disaster – can become incredibly dangerous, incredibly quickly.

When Fluid Dynamics Take Over

Imagine you’re waiting in a long line where volunteer aid workers are handing out hurricane relief supplies. There’s a huge group of people desperate for the supplies and a choke point where the volunteers are offloading the supplies from the truck.

As you move closer to the choke point, people start pressing tighter together. In a matter of moments, you go from standing shoulder to shoulder with people to being pressed on all sides by others. You can no longer choose which direction to go, and you are at the mercy of the pressure of the crowd.

At this point, fluid dynamics take over. You’ll feel yourself being swept off your feet and pushed forward by those behind you, who also have no choice but to lean into you. It’s like a river of people. You’ll lose your shoes the force is so strong.

The fluid dynamics of a dense crowd look like this:

Why and How Crowd Crush Becomes Deadly

The people near the back of the line are in the same situation you were in moments before. Things are tight but not too bad. They can’t see that people in front of them are struggling, and they really need those survival supplies, so they step a little bit forwards. Soon, they lose control too.

This type of situation has created several notable tragedies, such as the Station nightclub fire. At concerts and stadiums, people pushing to see the band have inadvertently killed people caught up in the crowd crush. The same situation happens as people are leaving a venue, rushing to get away from a fire or vying for sales on Black Friday.

Some people will get pressed up against a choke point like a stage, store doors, or, in our example, a truck where supplies are being unloaded. These people will soon be under such force they can’t breathe, and their internal organs may even be crushed under the weight of the crowd.

The choke point can sometimes relieve the pressure, such as when someone finally gets hold of some supplies and steps past the truck, but that only relieves them of danger. It isn’t enough to release the crowd’s pressure.

Other choke points can develop when people fall down, which they often do. The person leaning against them suddenly has nothing to brace against and falls too. It’s like dominoes, and soon the people near the bottom have so much weight on them that they can’t breathe.

How to Survive Crowd Crush

When you’re in a crowd that has become too dense, the number one thing to do is not work against the waves in the crowd. You’ll only fall. Instead, move perpendicular to the force of the crowd, especially in the lull between waves. If you can manage it, move diagonally backwards. Your best hope is to make it out on the side.

Do absolutely anything not to fall over, and try not to let anyone near you fall over – it’s not just altruism because you’ll be sucked down with them if they do. If you’ve noticed someone has fallen, try to help them regain footing in the lull between waves.

If you’ve fallen, form yourself into a stiff fetal position. Hold your arms and legs in front of your face and chest. Prepare to use them to push against the crowd’s force and to make room for your breathing.

Prepare for Crowd Crush

There are several things you can do before you get to this desperate situation to prevent it. First, always know where the alternative exits are and always move towards them. If you can get a group of people to move towards that exit instead of towards the primary exit, the safer everyone in the building will be.

Second, realize that most people decide to abandon the crowd when it is already too late. If things are getting dense, as in there are three or four people per square meter, you need to get out. At five or six people per square meter, you won’t be able to anymore.

Third, any venue can stop this phenomenon from happening simply by segmenting people into smaller groups. You’ll see in New Year’s Eve crowds where people are sectioned off from each other by barriers, which the wave effect can’t move through. These barriers must be tall, sturdy, and not curved at the bottom. You also have to carefully control how many people are allowed into the sections.

The bottom line is for you to know the situation before putting yourself into the mix. In an aggravated scenario, you are better off avoiding a situation even if it means not getting some supplies. After all, that handful of supplies won’t do you any good if you are one of those left behind, crushed to death on the ground.


Image courtesy of melis / Shutterstock