I just recently returned from an extended weekend up in Yellowstone National Park. I accompanied another photographer up to the Old Faithful area for my first time visiting the interior of Yellowstone in winter. Reservations for other tours had booked up quick, so we were left to wander around the Upper Geyser Basin for the duration of our stay, but did manage to get a cross-country ski in up to Biscuit Basin.
With so much snow falling this winter, bison were keeping to the warmer areas, in this case the geyser basins. In between plowing through snow for a minimal amount of food – just enough to keep them going – they would move over to where the ground was warm and relax there until it was time to eat again.