Astroworld festival: Big crowds can flow like liquid, with terrifying results

Large crowds are common during athletic contests, music concerts, political rallies, protest marches and even religious pilgrimages. When a crowd gets out of hand, a deadly surge like the one at the Astroworld music festival in Houston can result.

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Fatalities from last week’s music festival at NRG Park rose to nine on Thursday with the death of Bharti Shahani, 22, a Texas A&M University student.

When bodies are pressed together at an event, they react like fluid and move together as one unit, according to scientists.

“It was like a current, almost, in an ocean,” Reese Bludau, 20, who attended the Astroworld event, told KHOU. “You definitely weren’t moving your arms,” Bludau said, adding, “I had four to six people touching me at all times. It felt like I had probably 15 to 20 pounds on my chest and back.”

More than 50,000 people attended the event in Houston.

People who study crowds use different observational studies and mathematical modeling to understand how the masses behave, according to Smithsonian magazine. Scientists said that crowds will typically form lanes when people are walking in opposite directions, like in a hallway.

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However, when crowds become too dense, that organization begins to erode. When crowds are so close that they have to touch one another, people are unable to control their walking speed and direction to avoid collisions -- and crowd surges, according to Smithsonian.

Christopher Bergland, a retired ultra-endurance athlete turned science writer, wrote about his experience at a concert in Massachusetts in August 1982. Bergland, writing for Psychology Today in 2019, said that The Clash concert he attended at Cape Cod Coliseum was not equipped to handle waves of crowds surging toward the stage.

The problem, Bergland wrote, was that the owners of the arena “had haphazardly converted an old ice skating rink into a concert venue without giving much thought to crowd safety.”

“Because the concert was general admission with no assigned seats, everyone crammed onto the main floor, which became a mosh pit,” Bergland wrote, noting that he arrived early to the concert and was standing near the stage.

As the band played “Magnificent Seven,” Bergland said, the crowd pushed forward, smashing his body against a concrete barrier.

“Each wave of collective movement from the sold-out crowd pushed my lower body against the waist-high blockade with more and more force in a way that felt like it might split me in half,” Bergland wrote. “Luckily, some security guards finally started pulling people up over the barrier before we were pulverized by the sea of humanity unwittingly crushing us in waves that started at the back of the arena.”

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Surges through a crowd can lift people off their feet, rip off their shoes and tear clothing, Business Insider reported.

The surge can also carry people 10 feet or more, according to a 1993 paper by retired research engineer John Fruin. The intense pressure and warmth from bodies pressed together, paired with anxiety in a high-stress situation, can make it difficult to breathe, Fruin wrote.

If people faint, the only way to remove them from the flow of the crowd is to lift the person and pass them overhead to the edge of the crowd, Fruin wrote. Otherwise, a person runs the risk of being trampled.

Crowd flow is not limited to concerts. In 2006, a haji pilgrimage to Mecca became deadly when people rushing large stone walls tripped over luggage, Smithsonian reported. Hundreds were killed and more than 1,000 people were injured, according to The Guardian. At the same pilgrimage in 1990, more than 1,000 people died when a stampede occurred in an enclosed tunnel, the newspaper reported.

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In 2010, the Love Parade, an electronic dance festival in Duisburg, Germany, resulted in 21 deaths and more than 500 injuries, according to the BBC. The attendees were killed when thousands of attendees tried to navigate through narrow entry tunnels into the event, the network reported.

“Stop-and-go waves” are a warning sign for a dangerously dense crowd, Dirk Helbing, a computational social science researcher at the Swiss Federal Institute of Technology, told Smithsonian.

People wait for gaps in the crowd because there’s no space to move organically, Helbing told the magazine. If someone falls, stumbles, or is pushed, it can create a “black hole effect,” where more people are sucked into an empty space and fall.

“It’s really a terrible thing,” Helbing told Smithsonian.

Time can replace distance, researchers Brian Skinner, Ioannis Karamouzas, and Stephen J. Guy wrote in the 2014 journal, Physical Review Letters

The authors argue that people do not have to take evasive action while walking next to someone moving in the same direction. People will adjust their paths based on subconscious mental calculations so they do not collide, the authors wrote.

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When people are so densely packed that they are touching one another, they often cannot control their walking speed and direction to avoid collisions, the authors assert.

To avoid problems, Skinner said people should keep their heads up and scan a larger area to detect any potential areas of concern.

“The further you can look into the future the better you can move through a crowd,” Skinner told Smithsonian. “Looking three or four seconds into the future gives you an advantage over people who are only looking one or two seconds into the future.”

Crowd scientists said victims of crowd surge are not to blame, Business Insider reported.

Poor organization, which does not take crowd flow into consideration, can make attendees powerless to escape from a tsumani-like wave from a mob. Addressing bottlenecks before an event, along with holding event organizers accountable for crowd safety, are solutions, according to Business Insider.

“I’ve not seen any instances of the cause of mass fatalities being a stampede,” Keith Still, a British crowd science and risk analysis expert, told The Guardian. “People don’t die because they panic. They panic because they are dying.”

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Astroworld aftermath Stacey Sarmiento places flowers at a memorial in Houston on Sunday, Nov. 7, 2021 in memory of her friend, Rudy Pena, who died in a crush of people at the Astroworld music festival on Friday. (AP Photo/Robert Bumsted) (Robert Bumsted/AP)

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