I was 7 years old for the '66 blizzard and our Silver Spring neighborhood was buried. We had tons of fun tunneling through drifts. The biggest one I can recall was about 8-10 feet tall and completely blocked access to the front porch and door of a good friend's house. Another, in his backyard, was about 5 feet but was a consistent 5 feet all over his flat backyard, except the area right against the house which had so little snow you could see the grass.