Spilling Thought: So much affects the appearance of a #geyser: temperature, wind, quality of light and the mysterious plumbing of the geyser itself. As it sends water over a hundred feet into subzero air, a winter eruption of #OldFaithful often creates plumes of steam that cover the sky. Thinking about a winter adventure in #Yellowstone? Start planning at www.nps.gov/yell, and be sure to follow us @yellowstonenps (NPS photo by Jim Peaco). by usinterior