The streets were an opalescent white - with fog -
and never have my dreams been so shaken.
To wake up from a nightmare - like this -
throws us in a world of catatonic Dread.
(Now, wake!)
The streets were an opalescent white - with fog - < Take out the "with fog". I think that the feeling of this isn't snow, it's the lack of colour. We can feel the fog rather than know it, if that makes any sense. It is somehow too specific for what you're doing, and unnecessary.
and never have my dreams been so shaken.
To wake up from a nightmare - like this -
puts us in a new world of catatonic Dread. < I agree with Snoink here in that it should be changed. Not because of the "puts" as such, but because it's too long, too many sounds in comparison to your other lines. Shorten this to "a new..." and your intent is clear while we up the drama, the lyricism of it.
(Just try to wake up.) < (consider below revision)