This is the best page I've seen on Hypomelanism. It gets a little too "genetic science" for some but it explains a lot. (I've read it at least 20 times, lol)
http://www.dachiu.com/beardeddragoncare/hypomelanism.html
Snow is a light colored dragon, kinda like you day yellow or red. I tend to think of a snow as a light colored dragon that is not hypo ( clear nails).
If she is het for hypomelanism and you breed her with another het, or a visual hypo(clear nails) you will get some hypos. If she isn't a het, and you breed her with a hypo, you get all hets.
oh yeah... there are no hypos with dark nails,
all hypos have 20 clear nails.
Recessive trait genetics can be a little confusing, but it gets easier to understand with time.
Jeff