SEEKING INSIGHT INTO TRIGGERS
• A stampede Thursday near the holy city of Mecca during the peak of the annual hajj pilgrimage is just the latest in a regular string of such events at the site, but it’s the deadliest one in 25 years.
It’s hard to imagine how a crowd — especially one gathered for a peaceful religious rite — can turn so deadly. But the phenomenon is so common, experts in crowd management are consulted for most highly-trafficked events.
While many researchers focus on how to prevent stampedes by keeping spaces from getting overcrowded, there has been little research on what happens once a stampede starts — or why it begins.
In 2010, a review of all available literature on stampedes found that they’re on the rise. But researchers noted little was known about the actual triggers for these events. First responders, they said, were rightly focused on finding and treating the injured, not on taking detailed notes of their observations of the stampede.
“International health organizations have to recognize that this is an important type of disaster,” Edbert Hsu, associate professor of emergency medicine at Johns Hopkins, said at the time. “If they made it a protocol to send someone to a trampling disaster quickly to see what happened, we would have detailed reports we could use to compare and contrast. Without (those reports), we won’t really understand what we’re dealing with.”
Mechanically, stampedes are tragically simplistic. When
This is an important type of disaster
people are pushed tightly against one another (about seven people per 10 square feet of space, according to one study) it’s vital those in the front keep moving as quickly as those behind them. Otherwise, the people in the back — unable to see the front of the crowd — will move forward seeking more space, assuming that those in the front will continue to move to make way.
If the paces become mismatched — because something is blocking the front of the group, or a rumour spreads in the back that people are being crushed, causing folks to speed up — the front of the group gets squeezed, sometimes producing enough force to crush people where they stand.
It’s likely that the most deadly stampedes begin with a few deaths, the result of the sheer force of the tightly packed group, that then cause mass panic. Smaller stampedes may not be fuelled by panic at all — people can be crushed by the weight of those around them without anyone consciously surging forward.
Experts have argued most stampedes probably can be boiled down to the physical limits of their location. If people vying for space could be calm, stampedes of this magnitude wouldn’t occur. But faced with death, most will be slave to a racing heartbeat and hyperventilation — and an urge to run for safety at any cost.