Published on July 1, 2020.

Too Close for Comfort

NFPA's Victoria Hutchison recounts an unnerving encounter with a high-density crowd


One phenomenon that our computer vision research project on crowd management hopes to address is high-density crowds, where people become packed together so tightly that the only movement available to them is the collective motion of the crowd. As they have demonstrated time and again, crowds of this density can become deadly.

I experienced this phenomenon in 2014 when I was an undergraduate at Oklahoma State University in Stillwater, Oklahoma. Early that spring, the OSU Cowboys faced the fifth-ranked Kansas University Jayhawks in a basketball matchup at OSU’s Gallagher-IBA Arena. I was there, in the middle of it all, part of the crowd that packed the bleachers like sardines, eight rows behind the home-end basket. The matchup was billed as the best home game of the season, and noise and excitement rippled through the sold-out arena for the entire game. In the final moments, the Cowboys pulled away to win it, upsetting the favored Jayhawks. A rowdy celebration ensued, and fans prepared to storm the court as the final buzzer sounded.

Packed in among the crowd, I had two options: rush the court or be trampled. So I joined in, bounding down the bleachers, being pushed and shoved from all directions, anxiously moving toward center court. It seemed like I was trying to move through a sea of feet, and I tripped; I could feel myself falling as the crowd continued to move me forward. For a split second I was consumed by panic. Fortunately, a friend was next to me and able to quickly lift me up, and we kept moving in the giant scrum of bodies. We went until we could no longer move forward, waiting for whatever happened next.

That’s when the ordeal really began. We’d stopped, and all of the people in front of us had stopped, but the crowd behind us continued to pour onto the court, pressing into every available inch. The space around me shrank, then became none at all. I was in contact with everyone around me, front-to-back and side-to-side. The density of the crowd was immense, and I could feel the pressure of all that contact increase. For a period of time, I felt as if I had no individual physical control, that I was merely an involuntary part of the mass. The only motion I experienced was from the pulses that radiated through the crowd like shockwaves. I was overheated and very anxious, and I kept telling myself to stay calm.

Eventually, the pressure began to subside. Space once again appeared around me as the crowd dispersed and the celebration died down. Although the excitement of the big win still consumed us, I was relieved at actually being able to move again. We left the arena unscathed and elated, but history has shown repeatedly that the consequences of high-density crowds can be harsh, and sometimes lethal.

In these crowds, there is a vast array of psychological and physiological pressures that can impact the human body. When crowd density reaches approximately five to seven persons per square meter, the group begins to behave as a single fluid mass. If people in the rear are pushing forward, those in the front can be crushed against one another or into physical barriers with as much as 1,000 pounds of force. Such extreme pressure can result in a condition known as compressive asphyxia, which can cause erratic breathing, unconsciousness, and death. Most of the 96 people who died in a crush incident in 1989 at Hillsborough Stadium in Sheffield, England, during a soccer match succumbed to asphyxia, the result of an agonizing buildup of pressure caused by people crowding into viewing areas and trapping spectators in front against chain link fences. In these situations, people not overcome by the physical pressure can faint from the heat emitted by the large mass of bodies, or be overtaken by extreme psychological reactions such as anxiety and panic.

Looking back on that night at the basketball game, I realize that the crowd management strategy had been successful. Barriers had been removed, and safety officials allowed portions of the student section to storm the court while preventing others from following. To the best of my knowledge, there were no reported injuries. Even so, in venues like this, spectators often take their safety for granted, and may not act until it’s too late. That’s why crowd managers need relevant, timely, and accurate information to inform their decisions during dynamic events, which often must be made in just seconds. The data generated by our crowd density tool, such as crowd counts and trends in crowd density, aims to help safety officials make those decisions in critical moments, preventing near-misses from turning into tragedies.

VICTORIA HUTCHISON is a research project manager with the Fire Protection Research Foundation. Top photograph: Getty Images