There’s a scientific explanation for last week’s deadly crowd surge at the Astroworld music festival in Houston.
When people are loosely packed in …
There’s a scientific explanation for last week’s deadly crowd surge at the Astroworld music festival in Houston. When people are loosely packed in a crowd, with fewer than four people per square meter, they have room to make and act on their own decisions. But when crowd density rises above four people per square meter, and especially to six or more, something strange happens: People get pressed together so tightly that they begin to move together as one unit, with waves of pressure and release. In other words, human bodies behave like a fluid. That appears to be what happened at Astroworld on Friday. « It was like a current, almost, in an ocean, » Reese Bludau, a 20-year-old who was in the crowd, told Houston’s CBS affiliate, 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. » Shockwaves that travel through a densely packed crowd can be forceful enough to lift people off their feet, suck off shoes, tear off clothing, and carry people 10 feet or more, as retired research engineer John Fruin explained in a 1993 paper. The intense pressure and warmth from bodies pressed together, coupled with anxiety in a high-stress situation, can also make it difficult to breathe.
