got some of this fog in finland on 1.1.2025 ~20:20-23:40. i hadn't read of similar occurrences yet, but i immediately felt the fog was unnatural when i stepped into it to start up my car. winter fog is not exceedingly humid, usually made of little ice crystals, but it still feels slightly humid to the touch and adheres to surfaces over time, creating a white frost. while suspended, it also reflects and scatters light easily, to the point the glare is often a problem when driving. this fog was completely dry. no frost anywhere despite roughly -10c dropping temperatures. it smelled like sulfur. it was also extremely dark; it didn't scatter light, it absorbed light. wherever there was no direct light, the environment was unnaturally dark, getting near black 50 meters out or so. i breathed it in direct contact for approximately 20 minutes, and an hour through my car's filtration system. 3 days later, i'm coming down with a nasty sore throat. no other symptoms as of yet. all i can say, it was not a natural phenomenon. it was most likely testing grounds for a more serious, coordinated biological attack on population centers in the future.
Finland