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Waffle House has closed hundreds of restaurants as the coronavirus spreads around the US — a sign, chain aficionados say, that the pandemic has become a full-blown national crisis.

The Georgia-based diner chain known for staying open even in the wake of hurricanes and tornadoes has shuttered 365 locations, according to a Tuesday Facebook post. While 1,627 of its restaurants remain open, Waffle House fans say the closures demonstrate just how serious the virus crisis has become.

“I don’t think there’s a higher danger level than Waffle House closure y’all,” one observer said on Twitter.

“I swear I’ve eaten at a Waffle House where a tree came in the front window and good chunks of roof came off in bad weather and they just kept right on serving like it was a Tuesday,” another user wrote.

Waffle House’s dedication to staying open even in the worst of times led the Federal Emergency Management Agency to create the “Waffle House Index,” an informal measure of the severity of a disaster. The index, coined by former FEMA boss Craig Fugate, is “green” if one of its restaurants is serving a full menu, “yellow” if the menu is limited and “red” if the eatery is closed altogether.

“The Waffle House test doesn’t just tell us how quickly a business might rebound — it also tells us how the larger community is faring,” FEMA’s Dan Stoneking wrote in a 2012 blog post. “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.”

Waffle House said just a week ago that all of its restaurants were open at least for to-go service. Eateries across the country have scaled back to takeout and delivery service or closed altogether as states ordered residents to stay home to stem the spread of the deadly coronavirus.

Waffle House isn’t the only restaurant chain suffering because of the virus. Darden Restaurants, the Florida-based parent company of Olive Garden and LongHorn Steakhouse, has closed its dining rooms and reported a 5.9 percent drop in same-restaurant sales from late February through March 15.