This is how Waffle House stays open during storms — including using a natural disaster playbook, emergency teams, and limited menus

Waffle House is famous for staying open through hurricanes, tornadoes, blizzards, and other natural disasters.

The beloved restaurant chain, with 1,900 locations mostly in the southern US, is open 24 hours a day, 365 days a year. Waffle House takes natural disaster preparation so seriously that it’s become an unofficial metric to measure the severity of storms for the Federal Emergency Management Agency, known as the “Waffle House Index.”

The index has helped government officials and locals understand how conditions are on the ground during natural disasters since it was coined in 2011 by former FEMA administrator Craig Fugate.

The index is green if a Waffle House location is open and serving its full menu. It is yellow if it’s open with a limited menu. When the restaurant is closed, the index is red and indicates severe weather. “If you get there and the Waffle House is closed? That’s really bad. That’s where you go to work,” Fugate said in 2011.

Every location is armed with a “Waffle House storm playbook” that has protocol for keeping the restaurant running in an emergency, including if electricity and running water are unavailable, Waffle House Director of External Affairs Pat Warner told NPR. Restaurants can stay open as long as natural gas is up and running, with employees even boiling water on the grill for coffee.

The company shifts to a grill-only menu during natural disasters, Waffle House said. Waffle irons don’t work without electricity, but customers can still order anything on the grill including eggs, sausage, and hamburgers. When cash registers aren’t working, customers can pay in cash.

When a storm is on the forecast, Waffle House also brings in its mobile command center, an RV equipped to track the storm. The chain sends in “jump teams” of restaurant managers from areas unaffected by the storm to take over grills while regular employees are unable to get to work. Company leaders work from the headquarters in Atlanta to monitor the storm, direct jump teams, and source supplies like portable toilets and construction teams.

Sales can be double or triple normal levels after a disaster, The Wall Street Journal reported.

“If you factor in all the resources we deploy, the equipment we lease, the extra supplies trucked in, the extra manpower we bring in, a place for them to stay, you can see we aren’t doing it for the sales those restaurants generate,” Warner told WSJ.