Critical mass: When does a crowd become dangerous

There was an interesting article in the UKs' The Guardian a few months ago entitled "Critical mass: When does a packed but happy crowd become a dangerous, even lethal one?" which discusses as the title suggests when does a crowd become dangerous? The article starts with an incident in occurring at a Walmart's store in the US on Black Friday in 2008 where a crowd rushed into a store searching for bargains and a security guard died in the rush.

The reason I am blogging about it is that the paper sums up quite nicely and in understandable way the use of pedestrian modeling to understand such events and ways to potentially mitigate such occurrences from happening again.

One line I like is this that "in the almost weekly occurrence, somewhere in the world, of someone being injured or killed in a crowd." Other incidents for example, include the opening of the Primark flagship store in London in 2007 (below) or Jamarat bridge incident, where in 2004 more than 250 people were killed during a ritual part of the hajj known as the "stoning of the devil".

Shoppers at the opening of Primark in London tussle to get into the store (see the article).

Muslim pilgrims walk over a Jamarat bridge during the 'Jamarat' ritual, in Mina near Mecca.

The full article can be found here.