At least 149 dead in Seoul Halloween crowd crush, officials say

A crowd crush or surge, like the one in Itaewon on Saturday, is a stampede, said G. Keith Still, a crowd safety expert and visiting professor of crowd science at the University of Suffolk in England. A crush or surge happens when people are packed together in a confined space and there’s movement such as pushing that causes the crowd to fall over. Essentially, Still said, it’s a “domino effect.”

A stampede implies that people had space to run, which was not the case in Itaewon, he added. The more people in the crowd, the greater the force of the crowd crush is.