Riding through 4-6 inches of fresh snow is damn hard work to the point of being impossible. Unless you are almost putting in spint power you are going so slow that it is hard to control the bike.
Riding at speed (20kmh) on tyre tracks is extremely difficult and as soon as you veer into the fresh snow it is almost like doing an emergency stop (but less controlled)
Andy, this is spot-on with my own experience, especially here in Oregon's Southern Willamette Valley, where the snow falls wet, melts, recrusts, and then gets snowed on again. The tire (tyre) tracks are almost the worst...like riding in a box, and if you hit the sides...down you go (or nearly so; takes real watching, which is fatiguing as well).
It sure puts one's senses on High Alert, though. Makes y'feel alive! Till you almost aren't, anyway. Please do be careful, Andy; I'd hate to hear of you getting hurt if car traffic doesn't have quite as good traction as you do on the Nomad.
Loving the Wintry Ride Reports!
All the best,
Dan. (...who worries cars sometimes won't do as well on the slippery-slick as you do!)