When the zombies come head for the hills, say Cornell researchers

If a zombie outbreak occurs you should not rush to flat farmland, as Atlanta refugees did in the series ‘The Walking Dead’, instead you should head for the hills, which in the US means the Rockies, a team of researchers from Cornell University say.

Matthew Bierbaum, Alex Alemi, Christopher Myers and James Sethna were inspired by a graduate statistical mechanics class and the book “World War Z” by Max Brooks, which later became a movie starring Brad Pitt.

They set out to determine how a real zombie outbreak in the US might play out.

Zombie outbreak

If you headed for the hills straight away, you would have more time to organize a counterattack.

The research team will present their work modeling the statistical mechanics of the “undead” at the 2015 American Physical Society March Meeting (Thursday, March 5th) in San Antonio, Texas.

Mr. Alemi said that modeling zombies is not that different to techniques used to simulate what might happen with real diseases “albeit in a fun context.”


The team’s work offers an interesting introduction into disease modeling, and also some statistical physics techniques for measuring second-order phase transitions.

Mr. Alemi said:

“It’s interesting in its own right as a model, as a cousin of traditional SIR (susceptible, infected, and resistant) models – which are used for many diseases – but with an additional nonlinearity.”

According to PHYS.ORG:

“All told, the project was an overview of modern epidemiology modeling, starting with differential equations to model a fully connected population, then moving on to lattice-based models, and ending with a full U.S.-scale simulation of an outbreak across the continental U.S.”

Cities would fall fast

Mr. Alemi and colleagues found that if a zombie outbreak occurred, cities would fall rapidly, but it would take several weeks before less populated areas were invaded. The northern parts of the mountain-time zone in the US would be penetrated many months later.

Cornell team

The Cornell team: Alex Alemi (top left), Matthew Bierbaum (top right), James Sethna (bottom left), and Christopher Myers. (Source: Cornell University)

So, if you want the best chance to survive as long as possible, and maybe organize a counterattack, head for the Rockies, they advised.

In their simulation, there were four states an individual could be in: 1. Uninfected Human. 2. Infected. 3. Zombie. 4. Dead Zombie. This would depend on a number of possible interactions, such as the zombie bites a human, a human kills a zombie, zombie moves, etc.

Mr. Alemi said:

“Given the dynamics of the disease, once the zombies invade more sparsely populated areas, the whole outbreak slows down – there are fewer humans to bite, so you start creating zombies at a slower rate.”

New York City would fall within 24 hours, the researchers estimated, but upstate New Yorkers would have about a month to prepare.

The team says it plans to add more complicated social variables to their modeling, including the ability to make a dash for it and awareness of the zombie outbreak.

Interestingly, the researcher’s conclusions are not that different from Max Brooks’ book, with two-thirds of the US becoming abandoned and people retreating behind the Rockies, where they regroup and then launch a counterattack.