The "Waffle House Index" is an unofficial metric used to determine the severity of Hurricane Idalia and other storms in the U.S., and has existed for nearly 20 years.

Florida Emergency Management Director Craig Fugate coined the term "Waffle House Index" in 2004 after Hurricane Charley. The term was inspired by Waffle House's reputation for staying open during extreme weather and quickly reopening after hurricanes, tornadoes or other severe weather events.

The indicator was a passive way of learning the damage severity in a region, using the number of Waffle House locations that remained open in the aftermath of a storm to determine how much assistance may be required for disaster recovery.

The Federal Emergency Management Agency has been using the metric to measure a storm's severity.

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Waffle House

The "Waffle House Index" is an unofficial metric used to determine the severity of Hurricane Idalia and other storms. (iStock)

"Waffle House became almost like a rough guidepost," former FEMA director Craig Fugate, the creator of the index, told Fox Business in 2019. "If it was open and had a full menu we probably weren't in the worst-hit areas yet."

The index assigns color codes to measure the impact a natural disaster has on an area.

The color green indicates that the Waffle House has a full menu, meaning the restaurant has power and little or no damage. 

Yellow is for a limited menu, which shows that the restaurant has no power or only power from a generator, or that food supplies may be low. 

Red means the restaurant is closed and indicates severe damage or severe flooding to the area.

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Waffle House store

The index assigns color codes to measure the impact a natural disaster has on an area. (Getty)

"A lot of people will think, well, they're staying open so they can make more money," Waffle House Vice President of Public Relations Njeri Boss told Fox Weather in 2021. "In fact, we lose money on these disasters. It's not about money. It's about the people, we're in the people business. And so over the years, we've learned what people need in terms of trying to get a community back on its feet, in terms of helping our associates be able to take care of their families."

The bulk of Waffle House restaurants are located in the south, where many hurricanes hit. Hurricane Idalia is expected to make landfall in Florida and move up to Georgia, South Carolina and North Carolina.

"We actually have a storm playbook that every restaurant has. We revise it each year as needed. And it tells the management team what to do in the event of an emergency," Boss said.

Waffle House sign

The bulk of Waffle House restaurants are located in the south, where many hurricanes hit. (Getty)

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The Waffle House restaurants have limited menus for instances when they will be without water, electricity and gas, according to Fox Weather. If a Waffle House closes before a storm, it shows that extremely severe weather is expected and that people in the area should evacuate.

There are about 2,000 Waffle House locations in the U.S., including more than 400 in Georgia and more than 100 in Florida.