This happened a few days ago, just never got to posting it.
The cracking plant had a major upset, having to divert a great amout of the feed gasses to the flare. Seriously, you didn't need headlights that night, flare had a flame that would have been several stories tall.

Anyway, it was misty and cold that night. I mind my own business and noticed small, foam 'globs' falling from the sky. Not big, about the size of a credit card, just a bubbly mixture that complexed me.

My guess is that the flare was running so hot, plus any residual gasses not being burned, plus cold temperatures and humid air had mingled to make the 'foam rain'. Didn't last long and only a few puffs made it to our block but still.

Weird shit happens out here.