Started out in Bozeman, stayed a first night in Mammoth Hot Springs, stayed several days around Old Faithful, and then back to the Mammoth Hot Springs area for the Wolf Discovery tour.
Old Faithful Geyser with Icy Runoff Old Faithful Area, Yellowstone National Park, Wyoming
The runoff from eruptions caused the ice in the runoff channels to crackle and pop. It only did this loudly the first couple of days when it was colder. - February 02, 2011 - 1/500 sec at f / 11 - 20 mm - ISO 200 - 44°27'34" N 110°49'43" W