1986 San Francisco Fireworks fire:
http://www.sfgate.com/bayarea/article/SAN-FRANCISCO-Ceremony-to-recall-victims-of-2520438.php
30 years ago someone blew up a fireworks factory in SF causing numerous deaths, injuries and millions in damages and that's how Tandy destroyed the city
Considering that Forte was born and raised in the Bay Area in real life, I had hoped we would get to see what he and the other writers/producers had in store for the gang to find up there. (A charred wasteland, apparently. Friggin' Tandy!)
But yeah, it wouldn't surprise me if he remembered this before coming up with that flashback gag.
"I know I'm not normal -- but I'm trying to change!" ~ Muriel's Wedding