Snow does NOT wipe the bugs off!
Of course, it is very rare to spot any bugs when there is snow outside, but certainly not impossible. Not being able to see them surely does not mean that they are not around at all. Well, it is true that after laying their eggs, some bugs die out in cold temperatures. However, that is not the case with all ticks. There are some species of ticks that are dormant, even when it is cold, but they can survive through cold temperatures. It is a bit like winter hibernation for animals.
They usually hide in leaves and thick undergrowth, till the cold weather subsides. Now, you must be thinking that the snow on top of the leaves, should kill them. To our great disappointment, ticks are cold-blooded parasites, which means snow simply acts as an insulation from cold outside air for them.