If zombies took over the United States, how would it play out? A group of statisticians has done the worrying for us—and their work on a hypothetical zombie apocalypse has revealed that if the zombies do come, you’ll want to head for the Rocky Mountains.

Statisticians and zombies don’t always mix, but when a team of grad students from Cornell University wanted to study disease modeling, they turned to the undead. In an attempt to simulate the spread and effects of real diseases, the team followed a fictitious zombie outbreak. The team describes their experiment in a release:

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. It involved a lot of computational results generated from simulations the researchers wrote themselves. "At their heart, the simulations are akin to modeling chemical reactions taking place between different elements and, in this case, we have four states a person can be in—human, infected, zombie, or dead zombie—with approximately 300 million people,” [team lead Alex Alemi] explains.

The random nature of zombies, which could hypothetically bite, move or be killed at any given time, the researchers plenty of variables to work with.

So what did the apocalyptic analysis reveal? While pop culture usually imagines that an outbreak would affect all areas at once, the team found that the effect of a zombie apocalypse would slow as the zombies reached less populous areas. Dense populations would be affected the most quickly, falling in a matter of days—but it would take months for zombies to reach places like the northern Rockies.

And disease modelers aren't the only ones who're leaning on hypothetical zombies to model disasters—a team-building company has been using zombies to teach preparedness skills in cities like Portland.