I know that back in the day a lot of hazardous/toxic shit would be dumbed in northern Minnesota, and they didn't seem like they really were all that careful...maybe the waste at these dump sites have started leaking into the air or something?

There is also a lot mining and shit that happens up there. Maybe they breached something in the earth that is slowly leaking in the air?

I live in southeastern Minnesota and it's raining here....that is odd in and of itself for February.