The sun’s out! What a change from the gray landscape and snowy conditions we’ve seen day after day in Yellowstone. Let’s head to the Upper Terrace at Mammoth Hot Springs for a winter hike around the loop called Upper Terrace Drive. During the summer season (April-early November), this road is cars only. When snow falls, it becomes the domain of folks on skis and snowshoes.
The Mammoth upper and lower terraces form a massive hill of travertine. Travertine is the result of thermal (HOT mineral-laden) water rising through limestone. The water carries large amounts of dissolved limestone (calcium carbonate) as it races to the surface. Upon reaching the surface, carbon dioxide is released depositing the calcium carbonate which forms travertine, the chalky white mineral that forms the rock of the travertine terraces. Travertine formations grow rapidly due to the “soft” nature of limestone. They also change quickly as we will see along the trail. One fascinating fact that continues to amaze me is that all the extremely hot water creating this entire travertine area comes through a fault line from Norris Geyser Basin about 20 miles south. That is some hot-water pipeline. So my friend, strap on those snowshoes and let’s go!