• Waffle House is known for staying open during many natural disasters.
  • The chain’s policy has provided an unofficial way for the Federal Emergency Management Agency to track the severity of a natural disaster. If a Waffle House closes, it suggests the event was bad enough to potentially have devastating effects on the economy.
  • Waffle House is monitoring Hurricane Michael, which has made landfall in Florida. 21 restaurants in the Florida Panhandle have been closed as of Wednesday afternoon, Waffle House spokesperson Pat Warner told Business Insider.

The Federal Emergency Management Agency has an unusual way to track the severity of a natural disaster, and it involves Waffle House restaurants.

The chain, whose restaurants are open 24 hours a day, 365 days a year, is famous for staying open during many natural disasters. When it closes, that suggests an event was especially bad and likely to have devastating effects on the economy.

Because of this, FEMA internally uses an unofficial “Waffle House Index” to track potentially dangerous events.

“If a Waffle House store is open and offering a full menu, the index is green,” a 2011 article in the magazine EHS Today says. “If it is open but serving from a limited menu, it’s yellow. When the location has been forced to close, the index is red.”

This doesn't just show FEMA how quickly a business might rebound, it also shows it how the larger community is doing.

"The sooner restaurants, grocery and corner stores, or banks can re-open, the sooner local economies will start generating revenue again - signaling a stronger recovery for that community," FEMA said in a blog post in 2011.

"If we are open quickly after the storm broke, that means the community is coming back and we are getting back to that sense of normalcy," Pat Warner, director of PR at Waffle House, said in an interview with CNN in September, just before Hurricane Florence hit.

In September, Waffle House announced on Twitter that its "Storm Center" was monitoring Hurricane Florence.

It confirmed on Twitter this week that the same team is tracking Hurricane Michael, which has made landfall in Florida.

Waffle House has already closed 21 restaurants in the Florida Panhandle as of Wednesday afternoon, Warner told Business Insider.

Waffle House has 2,100 restaurants across 25 states, most of which are in the South. It closed 20 stores during Hurricane Florence, which hit the East Coast in September, and 90 during Hurricane Irma.

Warner told CNN in September that Waffle House prepares for a storm's aftermath by having resources like generators, food, and staff at the ready outside (but close to) the impacted area so that it can reopen restaurants as soon as possible.

Hurricane Michael has been designated a Category 4 storm and is currently a more intense storm than Hurricanes Andrew and Katrina.