I've wanted to make a winter trip into the park for a long time.  My parents and I had gone on a snowcoach tour when I was a kid but I don't remember much, just that it snowed a lot that weekend.  And I took a trip about a decade ago on a snowmobile but that was before I was a photography nut.  A winter trip to the park has been long overdue.  Last winter came and went and I never found the perfect opportunity to make the journey.  This winter nearly passed me by as well.  I finally decided to just go for it and booked a seat on a snowcoach tour.  It turned out to be a great day.  If it wasn't for the blanket of snow on the ground I would have sworn it was spring - it was so warm and sunny!

Winter travel in the park does have its advantages.  Since travel is restricted to guided snowmobile tours or snowcoach tours the amount of traffic is considerably less than in summer.  The snowcoach driver still managed to find a few traffic jams though.  That is if you can call coming to a dead stop because there is a herd of buffalo walking leisurely down the middle of the road a traffic jam.  The animals tend to congregate on the roadways in the winter.  It is much easier and they use less energy to walk on the packed snow of the roads than to walk in the deep snow of the fields.  Winter is a rough time for all of the animals in the park - harsh weather and little to no food takes its toll so they do what they can to conserve energy throughout the winter.

Winter Bison Napping Elk

The geyser basins change dramatically in the winter.  The warmth of the thermal features keeps much of the area free of any snow and the additional water from the snow melt fills up pools and feeds springs that would otherwise be dry.  The lower temperatures of the water and air along with less sunlight also affects the thermal features.  Different types of bacteria and algae that aren't accustomed to the heat of summer flourish in the winter.  Colors in the pools change from the bright blues and greens of summer to cooler oranges and browns.

Bacteria Mat IIBacteria Mat near Pump Geyser, Upper Geyser Basin Yellowstone.
This formation was at one time a few blades of grass that blew into the waters of the geyser. Soon the bacteria starts to grow and forms intricate structures like this one.

All in all it was a fantastic day in the park.  I didn't get to see everything that I would have liked but there's always next winter.