One way to measure the severity of Tropical Storm Florence is by the number of locations of a popular restaurant chain that are open and serving customers.

The "Waffle House Index" gets its name from the 24-hour service diner chain. It's the Federal Emergency Management Agency's unofficial indicator for how an area is faring after a powerful storm.

Waffle House spokesperson Pat Warner said Saturday morning on Cavuto Live that there are 230 establishments in the storm's path and that 17 were closed.

"We're kind of an indicator of how quickly the community is coming back after a storm," he said.

'It Looks Like a Battlefield': Man Trapped in Home By Florence Speaks With 'Fox & Friends'

The index features three color-coded levels per Waffle House restaurant.

Green means that a Waffle House is open and serving a full menu. If the index is yellow, there may not be power at the restaurant. If it's red, the restaurant is shut down, and the surrounding area is likely in need of help.

"We kind of take pride in being that canary in the coal mine that we've been called," Warner said. "People look to us to see how the communities are coming back."

Watch more from Cavuto Live above.

John Kerry: Trump Has 'Maturity of an 8-Year-Old Boy With the Insecurity of a Teenage Girl'

LOOK: American Flag Shredded By Florence Flies Off North Carolina Coast

'Pretty Scummy': 'The Five' Blasts NYT for Now-Corrected Story on Haley's $52K Curtains