Waffle House restaurants don’t close unless absolutely necessary — so the shuttering of 18 Florida locations ahead of Hurricane Michael speaks volumes about the severity of the storm.

“We have closed these restaurants yesterday so our employees can be safe as Hurricane Michael comes on shore,” Waffle House spokesperson Pat Warner confirmed to Fox News.

“We have staged people and resources outside of the strike zone to come into the area after the storm passes. We will assess the damage and begin to reopen the restaurants as soon as it is safe to do so.”

Warner told USA Today he expected more to close before Hurricane Michael — now a Category 4 hurricane — makes landfall on the Florida Panhandle.

News4Jax reporter Vic Micolucci, speaking with Channel 4, took the closure of Waffle House’s Panama City locations as a sign things are serious.

“Waffle House is usually our last hurrah to get a warm meal, with protein and of course sugar, and friendly service,” Micolucci said.

“We saw 4 in PCB closed. That’s a sign that this is serious. Some were boarded up. Others weren’t.”

The popular Georgia-based diner chain, renowned for its 24-hour service 365 days a year, is often used as an indicator by local officials to gauge the severity of disasters or outages.

Waffle House’s emergency measures are so well-regarded, in fact, that the Federal Emergency Management Agency (FEMA) unofficially uses the restaurants’ status as an indicator for the severity of a natural disaster. The practice began after several Waffle House locations closed or were serving only a limited menu in 2004 when Hurricane Charley hit Florida, and FEMA officials noted the severity of the storm damage based on the fact that the chain never closes.

The “Waffle House Index” has three color-coded levels: Green means the restaurant is open and serving a full menu; yellow indicates the menu has been scaled back and there may be water but no power; and red indicates the restaurant is completely shut down and the area is likely in need of serious assistance.

Warner told Fox News in 2016 that while the chain does everything in its power to stay open, their “number one priority is the safety of our staff on the ground and our customers.”

Waffle House also activated its storm center earlier this year, during Hurricane Florence.