Stampede is a situation in which a group of people suddenly start running in the same direction, especially because they are excited, or frightened, or there is a situation in which a lot of people are trying to do, or achieve the same thing at the same time.
Non-human species associated with stampede behaviour include zebras, cattle, elephants, reindeer, blue wildebeests, walruses, wild horses, and rhinoceroses.
Some media sources refer to situations in which people are injured, or dead due to compression in very dense crowds as a stampede, but this is a misnomer; the more appropriate term would be crush, or crowd collapse. Crushes often occur during religious pilgrimages, and large entertainment events, as these tend to involve dense crowds, with people closely surrounded on all sides.
Human stampedes and crushes also occur as people try to get away from a perceived danger, as in a case where a noxious gas was released in crowded premises.
While reports often talk of panic, research has found that mass panic is rare; on the contrary, people continue to help each other at the risk of their lives.
According to experts, true stampedes rarely occur except when many people are fleeing in fear, such as from a fire, and trampling by people in such stampede conditions rarely causes fatal injuries.
It is important to note that crushes are very often referred to as stampedes but, unlike true stampedes, these can cause many deaths. Crowd density is really more important than size; a density of 04 people per sq m begins to be dangerous, even if the crowd is not very large.
Academic experts who study crowd movements, and crushing disasters oppose the use of the term stampede. The rhetoric of stampede is often used to imply that the crowd is animalistic, or mindless. Most reported stampedes are better understood as progressive crowd collapses; beginning at densities of about 06 or 07 people per sq m. Individuals are pressed so closely against each other that they are unable to move as individuals, and shockwaves can travel through a crowd which, at such densities, behaves somewhat like a fluid.
If a single person falls, or other people reach down to help, waves of bodies can be involuntarily precipitated forward into the open space. One such shockwave can create other openings in the crowd nearby, precipitating further crushing. Unable to draw breath, individuals in a crowd can also be crushed while standing.
A crowd crush as such ensues when a large crowd is trying to move in a certain direction to reach an objective, or in response to the need to move forwards due to events at the back, with those at the back pushing forward not knowing that those at the front are being crushed. This may happen if an exit expected to be open is blocked. The forces involved may be very large — sometimes guard rails that can withstand 1000 pounds of force are bent by the crushed crowd.
A common aftermath of a crush with serious consequences is that those responsible for the event, and news media blame the crowd, and the victims for being out of control, and causing the crush, sometimes to the extent of a full cover-up. Later analysis, may show that the disaster was largely caused (in the moral, and legal rather than physical sense) by actions of those planning the event, as in the Hillsborough disaster which killed 96 football spectators. The crowd was blamed for the incidence until investigations two decades later found manifold errors by those responsible for organising and controlling the football event, with members of the crowd then being regarded as hapless victims.
It is believed that major crowd disasters can be prevented by simple crowd management strategies. Human stampedes can be prevented by planned organisation, and traffic control. On the other hand, barriers in some cases may funnel the crowd towards an already-packed area, as in the Hillsborough disaster. Hence barriers can be a solution in preventing or a key factor in causing a crush.
One problem is lack of feedback from people being crushed to the crowd pressing behind. This feedback can be provided by police, organizers, or other observers, particularly those at higher elevations who can survey the crowd, and use loudspeakers to communicate, and direct the crowd. In some cases it may be possible to take simple measures such as spreading movements out over time.
A factor that may contribute to a crush is inexperienced security officers who assume that people’s behaviour in a dense crowd is voluntary, and dangerous, and start applying force, or prevent people from moving in certain directions. In the 1989 Hillsborough disaster, some police and stewards were so concerned with what they saw as possible hooliganism that they took actions that actually made matters worse.
There is risk of a crush when crowd density exceeds about 04 people per sq m. For a person in the crowd, a signal of danger, and a warning to get out of the crowd if possible, is the sensation of being touched on all four sides. A later, more serious, warning is when one feels shock waves travelling through the crowd, due to people at the back pushing forward against people at the front with nowhere to go.
One in the crowd has to be therefore aware of her surroundings. Look ahead. Listen to the crowd noise. If you start finding yourself in a crowd surge, wait for the surge to come, go with it, and move sideways. Keep moving with it and sideways, with it and sideways.
After the 1883 crush known as the Victoria Hall disaster which killed 183 children, a law was passed in England which required all public entertainment venues to be equipped with doors that open outwards, for example using crash bar latches that open when pushed. Crash bars are required by various building codes.