If you get there and the Waffle House is closed? That's really bad...[2]
— Craig Fugate, Former Head of the Federal Emergency Management Agency
The measure is based on the reputation of Waffle House for having good disaster preparedness and staying open during extreme weather, or reopening quickly afterwards.
https://en.wikipedia.org/wiki/Waffle_House_Index
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No kidding! The wiki page has been around since Sept 3, 2011.