Mors Kochanski www.customwoolenmills.com ( nice folks to deal with too) The boot suggestions are excellent, but for extreme cold this sock example demonstrates the need for extreme footwear in the form of Mucluks. I own Stegners from Minnesota, easilly folded up with socks, they are invaluable. Winter boots were a key item the Soviet authorities reminded people to keep for future retreats during WW2