I never want to hear another word about Wal-Mart is "evil."

Walmart's preparedness system helped the company emerge as a hero after Katrina, says Steve Horwitz, an economist at St. Lawrence University in Canton, N.Y., who studied the company's response.

"They know exactly what people want after a hurricane," he says. "One of my favorite stories from Katrina is that the most popular food item after a major storm like this is strawberry Pop-Tarts."

Katrina showed that Wal-Mart was willing to let its employees improvise when they encountered something no computer could predict, Horwitz says.

In Waveland, Miss., where a Walmart was badly damaged, "they sort of pushed all this stuff into the parking lot and basically gave it away to the community," he says. "In other places, they broke into their own pharmacy to get drugs for local hospitals."

Since Katrina, the Federal Emergency Management Agency has begun studying ways to work with the private sector during emergencies. And the state of Florida has actually hired Bryan Koon, Walmart's former emergency manager, to run its Division of Emergency Management.

"What I learned at Walmart helps me here to be able to make sure that we are putting those retailers in the best possible position to be successful in a situation like this," Koon says.

If most people can get what they need from stores after a hurricane, Koon says, agencies like his can focus on the less fortunate victims.

Read the whole thing: Big-Box Stores' Hurricane Prep Starts Early : NPR. If you know what to look for, you see Adam Smith's invisible hand, the Hayekian knowledge problem, and arguments against protecting consumers from "price gouging."