Most likely a set of footprints from a fellow photographer as they passed by looking for that perfect spot, for that perfect picture of the northern lights.
The warmest place along the frozen river. The temperature was around -9 F. With the aid of hand and toe warmers, plus multiple layers of winter clothes I was pretty warm. Probably not as warm as the people were around the bonfire.
I missed the bigger solar storm earlier in the night. By the time I got to the bridge on Old Glenn highway the storm was starting to die down.