It's more a matter of a vague memory followed by searching through the comic's function -- down some distance below the comic on the page there's a box where you can look for story sequences by titles. (It says "jump to a scene".) The titles are often kind of vague and each covers a number of pages; but if I can remember more or less in the sequence when something happened, I can usually hunt around for a bit and find what I'm after.
Also once in a while I reread chunks of the comic; so I expect I'd re-read that more recently than 2013. Agatha bringing down the lightning is one of my favorite bits.