I hunt an area on the Candian border, up in the elevations, where the yearly snow fall is between 150-200". Literally once the snow gets crotch high the deer will move closer to town in the thicker areas for cover and food. About a 15 mile treck!
One spring I saw a spectacle I would have never believed if I didn't see it with my own eyes. No joke, I watched over 100 deer line up and march up an old logging road heading North to the elevations...
I asked the locals about what I had seen and one of the gentleman says it happens every year, as he explained what had happened that unique day. They just don't know when, but usually end of March - beginning of April. I guess I was at the right place at the right time - lucky for me!