Here is a photo taken by Pace Cooper during a hike up Snake Mountain last week after over two feet of snow fell. That's Greda (the dog) checking out the drifts. Pace says many drifts were over head high. Snake Mtn is about half way between Roan and Rogers near the TN/NC line, and probably represents that region of the AT pretty well.
http://www.booneweather.com/misc/xmas20033a.jpg