If you came to Yellowstone’s Mammoth Hot Springs every day of the year, and observed the terraces closely, you would see changes from the day before. That is because nearby Terrace Mountain, is literally turning itself inside out…dissolving its limestone deposits underground and then redepositing them on the surface. Springs rapidly seal themselves up only to appear in new locations. So as a result, two tons of previously unseen calcium carbonate emerge on the larger Minerva Springs every day.

There are two ways to view the travertine terraces and mounds around Mammoth.

Upper Terrace Drive is a one-way, 1.5 mile road that winds around both active and extinct hot springs. Recent, now dry, deposits are stark white. Older deposits are grayer.

If you want to get up close to the formations, where you can watch the water flow and feel the steam, head to the Main Terrace area. Main Terrace area is covered with loop trails, most on wooden boardwalks due to the thin crust and ever changing landscape. Sixty five species of algae and bacteria thrive in the steaming groundwater here (up to 170 degrees Fahrenheit), causing all sorts of colors and shapes to emerge inside and along the edges of the pools.

Mammoth Hot Springs, the northern entrance to the Yellowstone and home to park headquarters, is one of only two ranger stations that are open all year and accessible by car even in winter. The other is Tower-Roosevelt about fifteen miles east of Mammoth.