LOGAN -- If a zombie apocalypse hit Cache County, 70 percent of the population would be devoured or infected within seven to 10 days.
The contamination and death toll would climb much faster in Weber County, and faster still in Davis. In the more rural counties of Morgan and Box Elder, the end would come much more slowly, because of the increased distances "the walkers" would have to walk.
So says James Powell, who teaches both math and biology at Utah State University, and who for years has used diseases from the headlines to teach his students how to chart the pace at which real epidemics spread.
"I think it's nice to be topical," said Powell, who on Friday in Logan will give an all-age workshop, "Mathematics and the Life-Impaired: How the Theory of Disease Predicts the Zombie Apocalypse."
"Over the years, I have had my students chart H1N1, and before that there was a rabies outbreak, and years before that we talked about the number of new AIDS cases worldwide. We've charted other diseases and the maximum growth rate, and how much death we should expect."
Powell said he is a lifelong science fiction fan.
"I've been watching science fiction movies since I was a rodent," by which he meant small child. "When I started searching for zombie material on the Web, I was stunned by how much stuff there was out there. There's a kind of zombie chic."
AMC's "The Walking Dead" has birthed a new generation of fans, but Powell's interest dates back to the first time he saw the 1968 horror classic "Night of the Living Dead." In between, zombie blockbusters have included "28 Days Later," "I am Legend" and "Zombieland," to name just a few.
But some films had slow zombies, and some had speedy ones. Some films had living dead that worked well with others of their kind, and some films had zombies that seemed oblivious to everyone who was not a potential entree.
Powell hit on his parameters when he discovered students on the USU campus who play Humans vs. Zombies, a live-action game played on many campuses since it was created in 2005 at Maryland's Goucher College.
The game begins with a limited number of "zombies" and many more humans, all wearing armbands to mark them as players. Zombies multiply by "tagging" humans, and humans can fend off zombies with Nerf guns, marshmallow guns, rolled up socks, or whatever non-harmful weapon is agreed upon.
"Zombies starve if they don't feed frequently enough, and humans can defend themselves," Powell said of the game's rules. "And here, part of the way they organized the game is that humans have cards, and when a zombie gets you, he gets your card, so they can keep track of the numbers. So they had all this data already collected," Powell said.
Powell worked from the game's website, www.humansvszombies, to determine his zombie rules. Then, factoring zombie behavior, USU Human vs. Zombie "mortality" rates, and the number of humans in Cache County, he determined 70 percent of humans would be dead in seven to 10 days, then more zombies would begin to starve, taking them out of the equation as well.
"The humans who were left would be the ones better at defending themselves," Powell said. "The humans would still be in danger, but the epidemic would have peaked."
Powell said he has not yet figured the epidemic rates for other Utah counties or the world, but places where people live closer together and interact more would hit their epidemic peaks much sooner, he said. Another factor Powell sometimes asks students to consider is the availability of a cheap zombie vaccine.
"Maybe something like coffee," he said.
Powell plans to leave his Friday night audience with a new respect for math and the power of epidemics, but also with a glimmer of hope for the 30 percent of people who would survive the peak of any zombie epidemic.
"I do aikido, and my dojo and I are going to work a few zombie attacks into the talk, and demonstrate zombie defense," Powell said. "It's a robust martial art, and you don't strike your subject, which could injure you and expose you to body fluids. Potentially, it's well-adapted to zombie defense."
USU professor James Powell will give a Science Unwrapped talk about mathematics, disease epidemics, horror films and the "zombie apocalypse" at 7 p.m. Friday in the Emert Auditorium of the Eccles Science Learning Center. Zombie costumes are welcome. The event is free. Call 435-797-3517 for information. To find the building on an online campus map, visit www.usu.edu/map, then search building code ESLC.