Extremely vigorous fermentation

I fermented a beer, which is now in the keg and carbed. I'll taste it for the first time, other than the FG sample, this weekend. But the oddest thing happened to me, and I wanted to know if it was common:

I saw signs of active fermentation within a few hours of pitching. I arrived home after work the next day (or maybe the day after that), 18-36 hours post pitch, and the most wonderful smell greeted me. Of course, it was hops, but I had never smelled them so far from the fermenter before. So I went to check on the beer, and the airlock was dry. Assuming it had been sucked in or something, I added more StarSan solution, only to watch it bubble up out of the airlock, leaving it dry once again within maybe 30 seconds. This was an S-type airlock, so I swapped it for a 3-piece airlock and the problem was solved.

It was an expired vial of WLP060, so I did a two step starter, decanted, and pitched. The calculators didn't say I overpitched, and it was only a 1.062 OG beer. Has anyone else experienced this? The S airlocks have always worked well for me up until this point, even when pitching two packs of rehydrated dry yeast (440 billion cells, supposedly).

 

I guess I should have been more clear: I didn't have any blowoff with this batch. I usually do start off fermentation with a blow off tube if I'm using a top cropping yeast (like 1318) or if I've overfilled the fermenter.

This time, it was the sheer volume of CO2 produced by the yeast that was pushing the solution out of the airlock and drying it out within seconds. No debris or beer was pushed up into the airlock.