The Dangers of Crowds
In the movies, crowd deaths usually look the same: a mob of people running for their lives, trampling anyone unlucky enough to fall in their path. In reality, crowd deaths are much more subtle. Actions as simple as leaving a concert venue or sporting arena can pack people together tightly enough to cause "crowd crush," when someone is compressed by a crowd so much that they suffocate because they can't inflate their lungs. A famous example occurred in 1979 at a concert of The Who, when only two of the 16 doors at the Riverfront Coliseum were opened. A crowd of waiting fans surged through, asphyxiating 11 people in the process. When a crowd is this compressed, it stops behaving like a throng of people and starts behaving more like a fluid. Shock waves can travel through the crowd with enough force to lift people and throw them 10 feet or more, often removing their shoes and tearing their clothing in the process. So how do you protect yourself? Move to the outer edge of the crowd if you start feeling uncomfortable. Stay aware of where the exits are, and try to use the closest one regardless of where the crowd is heading. And if you do feel you can't escape, stay calm and try to keep your balance until the crowd dissipates.
from Brain Stuff
Key Facts In This Video
A high density crowd is defined as a crowd where there are 6 or more people per square meter. At that concentration, people in the crowd begin to lose the ability to move on their own accord, and the crowd tends to behave a lot like a fluid. (0:47)
If the crowd is packed tightly enough, you can lose the ability to inflate your lungs. Suffocating in this way is known as "crowd crush." "Progressive crowd collapse" happens when one person falls, leading other people to fall in a domino effect that ends up crushing those on the bottom of the pile of fallen people. (1:08)
It's a misconception that people most often die in crowds due to mass panics and stampedes. The fact is that if you have enough room to run over your fellow humans in a stampede, those people probably have enough room to get out of the way. Likewise, very rarely do crowds experience mass panic and move in a panicked way. You can suffocate from crowd crush in a very calm crowd. (2:42)