With that much unplowed snow, unless you're willing to buy a ridiculous bike like a Surly Pugsley, you're not going to have much luck. Even with studded tires you can't navigate 17 inches of snow. Pugsleys have really super wide tires (like, 100mm wide or so) and can just ride over. Most people aren't willing to spend $2000 on a winter bike though.
Personally I ride when there are less than 4 inches of snow on the ground, which where I am is all but about 3 or 4 days a winter.
I've tried riding with more snow than that, but when I have to walk it up hills, and pedal hard to go DOWN hills (I stopped moving if I stopped pedalling) I gave up and went home for the car.
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Work: the 8 hours that separates bike rides.