As is often the case, most people wait until the last minute to prepare for the worst.

As reported by CBS Detroit, one Army Surplus store owner reports that preparedness equipment is flying off the shelves:

"We've been very busy. Unusually busy, I'd say," Orr told WWJ's Sandra McNeill. "It's definitely an increase, just in selling all the normal prepper stuff, end of the world stuff. A lot of water prep stuff, food, MREs — the military meals."

And there's been a substantial increase in the sale of a particular item they don't sell much of — a so-called radiation antidote called potassium iodide.

"It actually stops your thyroid from absorbing any radiation. So, it fills your thyroid with iodine, which it normally does anyways," said Orr.

Another popular request: gas masks. But most people looking for those will be out of luck.