Maybe not the smartest thing I have done my life, but Feb 1-2 1996, record set at Tower, MN -60 by an NWS oberserver. A group of us were at Ash River (north of Tower, mn), rode for three days. We purposely did not ride after dark, thinking was maybe not a good idea to ride after dark. Biggest problem was getting sleds started, followed by getting the tracks to spin. In the morning, Getting engines started took two, one operating the electric starter, one pulling on starter rope. (one sled would turn over, so pulled the plugs, then turned engine, then replaced plugs). Usually took three guys to get track to turn, one on each side pulling on track, and one operating the throttle. We had to stop periodically to check each other to make sure no one was getting frostbite on face and all skin on face was covered. The resort we stayed at had an outdoor hot tub, temps were somewhere less than -40 when we got in at dark, then sat in the hot tub to take the chill away. There was no traffic on the trails.