Yep, potatoes need to go in early, basically as soon as the ground is workable in the spring. We planted two weeks ago and I'm roughly 400 miles north of you. Snow won't hurt them as long as the leaves haven't emerged. Even if they have, it won't hurt them much. Subfreezing temperatures will kill any above ground leaves, but the plant will just produce new ones as soon as the weather warms back up.
