I grew up in Maine so i have some experience with snow (even more experience with a snow shovel). the 100" of snow is probably the total snow fall that NY has had. when you get 12" of snow in a storm that is the white puffy snow after a few days that 12" has probably shrank down to 6 or 8" from the top layers melting. as far as snow removal I have seen 20 foot high snow piles in big parking lots where they have used front end loaders to pile it all up. I have also seen work crews load snow into dump trucks from the snowbanks along the road and go dump them else where. as you pile up snow it also compresses from the weight.

I don't know if that was a clear explanation if not i will try to clarify it when there are more questions.