zombies would be ok because their organs are dead anyway, they do not need to maintain any of the normal bodily functions for survival, all they need is for their brain to remain in tact. vampires on the other hand I think would be the more likely to subcum to such shortcomings as they are still alive, they just need to drink blood. and if they are the stupid twilight vamps that twinkle they should just die off anyway because they suck
In the words of Queen - "It's a kind of magic."
Anyway, vampires can move around so fast they must be generating a lot of heat, if only through friction on their clothes.
And zombies would fall off the edge of the ice and be frozen in the ocean currents until they reach southern climes, like Florida.