Funny thing is climatologists have a great idea where the snow line was back then. The ice ages are well known and documented by the movement of glaciers. Long Island was formed by glaciers in one of the last ice ages. I believe the glacier stopped mid island, the melt water created the Long Island sound, and the rocky north shore and glacial merrains form the southern extent. So we can approximate the rain snow line periods past. Not precisely of course, but generally yes.
Any more questions?