Conditions didn't improve enough to warrant me hanging around any longer, so I began heading back down the mountain. The rest of the story is still like a bad dream, but I now have a new car and a set of SSC Super Z6 cable chains on order. Not sure why I didn't think of these before dammit.

http://www.scc-chain.com/Traction%20Pages/Trac_SZ6.html