A snowball made with early spring snow - soft and grainy-isn't white. If you dissect that snowball don't be surprised to find micro- bits of dust,droppings,plant debris,algae,and exhaust particles.
Today if conditions are right,sailers northwest of Scotland get glimpses of Iceland,Greenland ,and Labrador . It is possible that early European sailers ventured to the " New World" because they already saw it.