Particulate fecal depositions that originated from Mexico City. Strong winds that blow through poverty stricken towns aerates the feces, causing it to harden, and later eroding it into the atmosphere where it will later fall like snow.
Jose: It's snowing!
Chiquito: I don't believe you!
Jose: Look! It's dissolving in my mouth!
He later found out in his grave that it was fecal snow he was indulging his pleasures in.