The Terraces at Mammoth Hot Springs

Mammoth Hot Springs is at the north end of Yellowstone National Park and is one of the more active thermal areas, though for years now the activity has slowed. The white mounds in the picture are part of the terraces, but a part that is mostly inactive. I have pictures, however, from the 1970's that show at a great deal of activity in this area. In this area it is possible to walk through the terraces on boardwalks, just visible at the lower end of the picture and of the terraces, but otherwise the ground in these thermal areas is very unstable and very dangerous.