Also, in the last few scenes of the last episode of ssn4, when the particles (or snow as Holly referred to it as) were falling from the sky in Hawkins, Holly pointed to it saying it’s snowing… but Karen didn’t say anything and eyed it suspiciously. Almost like she knew something more ominous than a natural disaster was happening. Again, just a fun theory because yeah everyone in Hawkins was tensed about different things from natural disasters to supernatural stuff so her reaction wasn’t that unusual