In the rare event a Waffle House is completely shut down, the index is red and that usually means there's big trouble.

"I guess our reputation has been that if we're able to get back open, things might be bad, but they're not horrible," said Walt Ehmer, chief operating officer of the 1,600-store chain. "But, if we don't happen to be able to be doing business, then that must be a sign that the community is in really bad shape."

Current FEMA Director Craig Fugate came up with the Waffle House Index during his eight years responding to hurricanes as the head of Florida's Division of Emergency Management. In 2009, Fugate told an audience at the inaugural Random Hacks of Kindness, Disaster Relief Codejam event in Washington that practical indicators are much more informative than checking with a host of local utilities and law enforcement agencies when initially trying to assess a stricken area. And Waffle House is as reliable a practical indicator as there is, he said.