Waffle House, the restaurant chain known for its 24/7 openness, is closing locations in Tallahassee, Florida, and its nearby Crawfordville location ahead of Hurricane Helene’s landfall Thursday evening.

The chain rarely closes (it’s open 365 days a year), so it’s notable when the Waffle House restaurants close.

Years ago, a former local emergency manager in Florida created the “Waffle House Index.” USA Today explains, “As part of the index, Waffle House restaurants are ranked and marked with three different colors to indicate conditions and let officials know where to deploy first responders and supplies during emergencies.”

The ranking means:

People have started following the Waffle House Index to determine how bad a storm is. For example, if first responders are covering an area and see a closed Waffle House highlighted in red, that means an area is about to be hit by a storm or needs assistance.